Question

Expand using suitable algebraic identities:
a) (y+0.3) (y-0.3)
b) (3x-5y)^2
c) (2x+1/x)^2

Answer 1

Answer:

a)a square-b square

b) a square+b square- 2ab

Answer 2

Answer:

a) y²- 0.3²

b) 9x²-30xy+25y²

c) 4x²+ 4 + 1/x²

Step-by-step explanation:

a) the above bit is in the form of [a²-b²= (a+b) (a-b)]

so, write it as

y²- 0.3² = ( y+ 0.3) ( y-0.3)

b) it is in the form of [(a-b)²= a²-2ab+b²]

so,

it is (3x)²-2(3x)(5y)+ (5y)²

ie, 9x²-30xy+25y²

c) it is in the form of [(a+b)²= a²+2ab+b²]

so,

it is (2x)²+2(2x)(1/x)+(1/x)²

ie, 4x²+ 4 + 1/x²