Question

How do you multiply `(7x-y)(8x+9y)`?

Answer 1

`=color(blue)(56x^2 + 55xy -9y^2`

Explanation:

`(color(blue)(7x)-color(purple)(y))(8x+9y)`

`= color(blue)((7x) * (8x) + (7x) * (9y) )+ color(purple)( (-y) * (8x) + (-y) * (9y)`

`=56x^2 + 63xy -8xy -9y^2`

`=color(blue)(56x^2 + 55xy -9y^2`