Class 8 Expression Assignment 2

 

Class 8 Expression Assignment 2

 

Q1. Simplify the expressions and evaluate them as directed:

a)3x (4x-5) +3 for x=3

 

Ans:- 12x^{2 –} 15x +3

Now put x=3

12 (3)²   - 15X3 +3

108 – 45 +3

111-45 = 66

 

b) a(a²+a+1) +5 for a= -1

 

Ans:- a³ +a² +a +5

Now put a =-1

Value = 4

 

Q2. Find the product

a)  5a²b² (3a² -4ab +6b²)

 

Ans:- 15a⁴b² – 20 a³ b³ +30 a² b⁴

 

b) -3x²y (4x²y -3xy² +4x -5y)

Ans:- -12 x⁴ y² +9 x³ y³ -12 x³ y+15 x² y²

 

c)    3xy ( 2x²y ^_ 3x +4y)

6x³y² – 9x²y + 12xy²

Q3. Multiply

a)   (3x+5y) (3x-5y)

(a+b) (a-b) = a² – b²

(3x)² – (5y)²

9x² – 25y²

 

b)  (x-2) (x+2)

c)    (x+3) (x-3)

d)  (y+4) (y+4)

=

 

Q4. Expand

a)   (2x+5y)²

b)  (3x-4)²

c)    (2x+5) (2x-5)

d)