Question

Multiply these:
(i) (2x+5y) (3x-4y)
(ii) (2x+3) (2x-4)​

Answer 1

Answer:

1. (2x+5y)(3x-4y)

=2x(3x-4y) + 5y(3x-4y)

= 6x²-8xy+15xy-20y²

= 6x²+7xy-20y²

2. (2x+3)(2x-4)

Using identity (x+a) (x+b) =x²+(a+b)x+ab

Here a=3, b=(-4) Now putting the values in the identity

=(2x+3)(2x-4)=(2x)²+[3+(-4)]2x+3×(-4)

=4x²-5x-12