Question

For what value of a is the equation: (x + 7)2 = (x − 7)2 + ax an identity? (An identity is an equation in which any number is solution. For example, x + 3 = 3 + x is an identity.)

Answer 1

Explanation:

Hello, we need first to develop and then identify the like terms.

`(x + 7)^2 = (x-7)^2 + ax\\\\(x+7)^2-(x-7)^2=ax\\\\(x+7-x+7)(x+7+x-7)=ax\\\\14*2x=ax\\\\28x=ax`

So a = 28.

Thank you