NCERT Solutions for Class 7 Maths Chapter 4: Students can use Simple Equations to help them with their homework and exam preparation. We have developed NCERT Solutions for Class 7 Maths Chapter 4 step-by-step solutions with thorough descriptions for students who are anxious about tackling NCERT Solutions for Class 7 Maths Chapter 4. We advise students who want to improve their math grades to review these NCERT Solutions for Class 7 Maths Chapter 4 and broaden their understanding.
NCERT Solutions for Class 7 Maths Chapter 4 PDF
1. Complete the last column of the table.
S. No. | Equation | Value | Say whether the equation is satisfied. (Yes/No) |
(i) | x + 3 = 0 | x = 3 | |
(ii) | x + 3 = 0 | x = 0 | |
(iii) | x + 3 = 0 | x = -3 | |
(iv) | x – 7 = 1 | x = 7 | |
(v) | x – 7 = 1 | x = 8 | |
(vi) | 5x = 25 | x = 0 | |
(vii) | 5x = 25 | x = 5 | |
(viii) | 5x = 25 | x = -5 | |
(ix) | (m/3) = 2 | m = – 6 | |
(x) | (m/3) = 2 | m = 0 | |
(xi) | (m/3) = 2 | m = 6 |
Solution:
(i) x + 3 = 0
LHS = x + 3 By substituting the value of x = 3 Then, LHS = 3 + 3 = 6 By comparing LHS and RHS, LHS ≠ RHS ∴ No, the equation is not satisfied.(ii) x + 3 = 0
LHS = x + 3 By substituting the value of x = 0, Then, LHS = 0 + 3 = 3 By comparing LHS and RHS, LHS ≠ RHS ∴ No, the equation is not satisfied.(iii) x + 3 = 0
LHS = x + 3 By substituting the value of x = – 3, Then, LHS = – 3 + 3 = 0 By comparing LHS and RHS, LHS = RHS ∴ Yes, the equation is satisfied.(iv) x – 7 = 1
LHS = x – 7 By substituting the value of x = 7, Then, LHS = 7 – 7 = 0 By comparing LHS and RHS, LHS ≠ RHS ∴ No, the equation is not satisfied. (v) x – 7 = 1 LHS = x – 7 By substituting the value of x = 8, Then, LHS = 8 – 7 = 1 By comparing LHS and RHS, LHS = RHS ∴ Yes, the equation is satisfied.(vi) 5x = 25
LHS = 5x By substituting the value of x = 0, Then, LHS = 5 × 0 = 0 By comparing LHS and RHS, LHS ≠ RHS ∴ No, the equation is not satisfied.(vii) 5x = 25
LHS = 5x By substituting the value of x = 5, Then, LHS = 5 × 5 = 25 By comparing LHS and RHS, LHS = RHS ∴ Yes, the equation is satisfied.(viii) 5x = 25
LHS = 5x By substituting the value of x = -5, Then, LHS = 5 × (-5) = – 25 By comparing LHS and RHS, LHS ≠ RHS ∴ No, the equation is not satisfied. (ix) m/3 = 2 LHS = m/3 By substituting the value of m = – 6, Then, LHS = -6/3 = – 2 By comparing LHS and RHS, LHS ≠ RHS ∴ No, the equation is not satisfied.(x) m/3 = 2
LHS = m/3 By substituting the value of m = 0, Then, LHS = 0/3 = 0 By comparing LHS and RHS, LHS ≠ RHS ∴ No, the equation is not satisfied.(xi) m/3 = 2
LHS = m/3 By substituting the value of m = 6, Then, LHS = 6/3 = 2 By comparing LHS and RHS, LHS = RHS ∴ Yes, the equation is satisfied.S. No. | Equation | Value | Say whether the equation is satisfied. (Yes/No) |
(i) | x + 3 = 0 | x = 3 | No |
(ii) | x + 3 = 0 | x = 0 | No |
(iii) | x + 3 = 0 | x = -3 | Yes |
(iv) | x – 7 = 1 | x = 7 | No |
(v) | x – 7 = 1 | x = 8 | Yes |
(vi) | 5x = 25 | x = 0 | No |
(vii) | 5x = 25 | x = 5 | Yes |
(viii) | 5x = 25 | x = -5 | No |
(ix) | (m/3) = 2 | m = – 6 | No |
(x) | (m/3) = 2 | m = 0 | No |
(xi) | (m/3) = 2 | m = 6 | Yes |
2. Check whether the value given in the brackets is a solution to the given equation or not.
(a) n + 5 = 19 (n = 1)
Solution:
LHS = n + 5 By substituting the value of n = 1, Then, LHS = n + 5 = 1 + 5 = 6 By comparing LHS and RHS, 6 ≠ 19 LHS ≠ RHS Hence, the value of n = 1 is not a solution to the given equation n + 5 = 19.(b) 7n + 5 = 19 (n = – 2)
Solution:
LHS = 7n + 5 By substituting the value of n = -2, Then, LHS = 7n + 5 = (7 × (-2)) + 5 = – 14 + 5 = – 9 By comparing LHS and RHS, -9 ≠ 19 LHS ≠ RHS Hence, the value of n = -2 is not a solution to the given equation 7n + 5 = 19.CBSE Syllabus Class 7 | |
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(c) 7n + 5 = 19 (n = 2)
Solution:
LHS = 7n + 5 By substituting the value of n = 2, Then, LHS = 7n + 5 = (7 × (2)) + 5 = 14 + 5 = 19 By comparing LHS and RHS, 19 = 19 LHS = RHS Hence, the value of n = 2 is a solution to the given equation 7n + 5 = 19.(d) 4p – 3 = 13 (p = 1)
Solution:
LHS = 4p – 3 By substituting the value of p = 1, Then, LHS = 4p – 3 = (4 × 1) – 3 = 4 – 3 = 1 By comparing LHS and RHS, 1 ≠ 13 LHS ≠ RHS Hence, the value of p = 1 is not a solution to the given equation 4p – 3 = 13.(e) 4p – 3 = 13 (p = – 4)
Solution:
LHS = 4p – 3 By substituting the value of p = – 4, Then, LHS = 4p – 3 = (4 × (-4)) – 3 = -16 – 3 = -19 By comparing LHS and RHS, -19 ≠ 13 LHS ≠ RHS Hence, the value of p = -4 is not a solution to the given equation 4p – 3 = 13.(f) 4p – 3 = 13 (p = 0)
Solution:
LHS = 4p – 3 By substituting the value of p = 0, Then, LHS = 4p – 3 = (4 × 0) – 3 = 0 – 3 = -3 By comparing LHS and RHS, – 3 ≠ 13 LHS ≠ RHS Hence, the value of p = 0 is not a solution to the given equation 4p – 3 = 13.CBSE Board Exam Centre List 2024
3. Solve the following equations by trial and error method.
(i) 5p + 2 = 17
Solution:
LHS = 5p + 2 By substituting the value of p = 0, Then, LHS = 5p + 2 = (5 × 0) + 2 = 0 + 2 = 2 By comparing LHS and RHS, 2 ≠ 17 LHS ≠ RHS Hence, the value of p = 0 is not a solution to the given equation. Let, p = 1 LHS = 5p + 2 = (5 × 1) + 2 = 5 + 2 = 7 By comparing LHS and RHS, 7 ≠ 17 LHS ≠ RHS Hence, the value of p = 1 is not a solution to the given equation. Let, p = 2 LHS = 5p + 2 = (5 × 2) + 2 = 10 + 2 = 12 By comparing LHS and RHS, 12 ≠ 17 LHS ≠ RHS Hence, the value of p = 2 is not a solution to the given equation. Let, p = 3 LHS = 5p + 2 = (5 × 3) + 2 = 15 + 2 = 17 By comparing LHS and RHS, 17 = 17 LHS = RHS Hence, the value of p = 3 is a solution to the given equation.(ii) 3m – 14 = 4
Solution:
LHS = 3m – 14 By substituting the value of m = 3, Then, LHS = 3m – 14 = (3 × 3) – 14 = 9 – 14 = – 5 By comparing LHS and RHS, -5 ≠ 4 LHS ≠ RHS Hence, the value of m = 3 is not a solution to the given equation. Let, m = 4 LHS = 3m – 14 = (3 × 4) – 14 = 12 – 14 = – 2 By comparing LHS and RHS, -2 ≠ 4 LHS ≠ RHS Hence, the value of m = 4 is not a solution to the given equation. Let, m = 5 LHS = 3m – 14 = (3 × 5) – 14 = 15 – 14 = 1 By comparing LHS and RHS, 1 ≠ 4 LHS ≠ RHS Hence, the value of m = 5 is not a solution to the given equation. Let, m = 6 LHS = 3m – 14 = (3 × 6) – 14 = 18 – 14 = 4 By comparing LHS and RHS, 4 = 4 LHS = RHS Hence, the value of m = 6 is a solution to the given equation.Related Links -
4. Write equations for the following statements.
(i) The sum of numbers x and 4 is 9.
Solution:
The above statement can be written in the equation form as, = x + 4 = 9(ii) 2 subtracted from y is 8.
Solution:
The above statement can be written in the equation form as, = y – 2 = 8(iii) Ten times a is 70.
Solution:
The above statement can be written in the equation form as, = 10a = 70(iv) The number b divided by 5 gives 6.
Solution:
The above statement can be written in the equation form as, = (b/5) = 6(v) Three-fourths of t is 15.
Solution:
The above statement can be written in the equation form as, = ¾t = 15(vi) Seven times m plus 7 gets you 77.
Solution:
The above statement can be written in the equation form as, Seven times m is 7m. = 7m + 7 = 77(vii) One-fourth of a number x minus 4 gives 4.
Solution:
The above statement can be written in the equation form as, One-fourth of a number x is x/4. = x/4 – 4 = 4(viii) If you take away 6 from 6 times y, you get 60.
Solution:
The above statement can be written in the equation form as, 6 times y is 6y. = 6y – 6 = 60(ix) If you add 3 to one-third of z, you get 30.
Solution:
The above statement can be written in the equation form as, One-third of z is z/3. = 3 + z/3 = 305. Write the following equations in statement forms.
(i) p + 4 = 15
Solution:
The sum of numbers p and 4 is 15.(ii) m – 7 = 3
Solution:
7 subtracted from m is 3.(iii) 2m = 7
Solution:
Twice of number m is 7.(iv) m/5 = 3
Solution:
The number m divided by 5 gives 3.(v) (3m)/5 = 6
Solution:
Three-fifth of m is 6.(vi) 3p + 4 = 25
Solution:
Three times p plus 4 gives you 25.(vii) 4p – 2 = 18
Solution:
Four times p minus 2 gives you 18.(viii) p/2 + 2 = 8
Solution:
If you add half of a number p to 2, you get 8.6. Set up an equation in the following cases.
(i) Irfan says that he has 7 marbles, more than five times the marbles Parmit has. Irfan has 37 marbles (Take m to be the number of Parmit’s marbles).
Solution:
From the question, it is given that Number of Parmit’s marbles = m Then, Irfan has 7 marbles, more than five times the marbles Parmit has. = 5 × Number of Parmit’s marbles + 7 = Total number of marbles Irfan having = (5 × m) + 7 = 37 = 5m + 7 = 37(ii) Laxmi’s father is 49 years old. He is 4 years older than three times Laxmi’s age (Take Laxmi’s age to be y years).
Solution:
From the question, it is given that Let Laxmi’s age be = y years old Then, Lakshmi’s father is 4 years older than three times her age. = 3 × Laxmi’s age + 4 = Age of Lakshmi’s father = (3 × y) + 4 = 49 = 3y + 4 = 49(iii) The teacher tells the class that the highest marks obtained by a student in her class are twice the lowest marks plus 7. The highest score is 87 (Take the lowest score to be l).
Solution:
From the question, it is given that Highest score in the class = 87 Let the lowest score be l. = 2 × Lowest score + 7 = Highest score in the class = (2 × l) + 7 = 87 = 2l + 7 = 87(iv) In an isosceles triangle, the vertex angle is twice either base angle (Let the base angle be b in degrees. Remember that the sum of angles of a triangle is 180 degrees).
Solution:
From the question, it is given that We know that the sum of angles of a triangle is 180 o Let the base angle be b. Then, Vertex angle = 2 × base angle = 2b = b + b + 2b = 180 o = 4b = 180 o