CLASS-8

BOARD: CBSE

Mathematic Worksheet - 2

TOPIC: Algebra

For other** CBSE Worksheet for class 8 Mathematic**check out main page of Physics Wallah.

1) (a+b)^{ 2}=a^{2}+ 2ab+b^{2}

2) (a-b)^{ 2}=a^{2}- 2ab+b^{2}

3) (a+b)^{ 3}=a^{3}+ 3a^{2}b+ 3ab^{2}+b^{3}=a^{3}+b^{3 }+ 3ab (a+b)

4) (a-b)^{ 3}=a^{3}- 3a^{2}b+ 3ab^{2}-b^{3}=a^{3}-b^{3 }- 3ab (a-b)

5) (a^{3}+b^{3}) =(a+b) (a^{2}-ab+b^{2})

6) (a^{3}-b^{3}) =(a-b) (a^{2}+ab+b^{2})

7) (a^{2}-b^{2}) = (a+b) (a-b)

8) (a^{3}+b^{3}+c^{3}- 3abc) = (a+b+c) (a^{2}+b^{2}+c^{2}-ab-bc-ca)

9) (a^{3}+b^{3}+c^{3}) = 3abc if a + b + c = 0

10) (a+b+c)^{ 2}=a^{2}+b^{2}+c^{2}+ 2ab+ 2bc+ 2ca

**Linear equation in one variable:**

An equation involving a variable in the first degree is called a linear equation in one variable. It is of the form ax + b = 0, x is variable.

x= - b/a is the root or solution of this equation.

An equation of the form ax^{2} + bx + c = 0, where a, b, c are constant and a 0, is called a quadratic equation in one variable ‘x’.

**1) The factors of are:**

D) None of these

**2) In an examination a student was asked to find 3/14 th of a certain number. By mistake, he found 3/4 of it. His answer was 150 more than the correct answer. The number given to him is:**

A) 290

B) 280

C) 240

D) 180

**3) A man is 5 years older than his wife and the wife is now thrice as old as their daughter, who is 10 years old. How old was the man when his daughter was born?**

A) 20 years

B) 23 years

C) 25 years

D) 30 years

**4) If x + y=3 and xy=2, then the value of x ^{3}-y^{3} is equal to:**

A) 6

B) 7

C) 8

D) 0

A) 180

B) 140

C) 240

D) 100

A) 9, 6 or 9, -6

B) 5, 6 or 5, -6

C) 9, 5 or 9, -5

D) None of these

A) 9

B) 10

C) 11

D) 13

A) x

B) x

C) x

D) x

A) 45 years

B) 30 years

C) 15 years

D) 10 years

A) Rs. 25

B) Rs.10

C) Rs.35

D) Rs.40

A) 3x

B) 3x

C) 3x

D) 3x

A) ½(a+ b + c)

B) a +b + c

C) 3(a + b+ c)

D) 2(a b c)

A) 0

B) 1

C) x

D) x

A) 7

B) - 7

C) 3

D) none of these

A) 2/3

B) 3/2

C) 5/6

D) 6/5

A) 2x

B) 2

C) 1

D) 1/2x

A) 1

B) 2

C) 3

D) 0

A) 63

B) 54

C) 21

D) 42

A) 2

B) 7.4

C) 5

D) 84.14

20) If x= , then is:

A) 2(3- )

B) 6- 2

C) 6 -

D) 12

A) 16 tables 11 chairs

B) 15 tables 12 chairs

C) 13 tables 14 chairs

D) 10 tables 17 chairs

1) (C)

2) (B)

3) (C)

4) (B)

5) (B)

6) (A)

7) (B)

8) (D)

9) (C)

10) (C)

11) (D)

12) (B)

13) (B)

14) (B)

15) (A)

16) (B)

17) (A)

18) (C)

19) (A)

20) (D)

21) (A)