Question

when (2x - 3)^2 is subtracted from 5x^2, what is the result? And how can I show the answer? Thank you x

Answer 1

5x^2 - (2x - 3)^2 = 
5x^2 - ((2x - 3)(2x - 3)) =
5x^2 - (4x^2 - 6x - 6x + 9) =
5x^2 - (4x^2 - 12x + 9) =
5x^2 - 4x^2 + 12x - 9 =
x^2 + 12x - 9 <===

Answer 2

First expand (2x-3)^2
(2x-3)(2x-3)=(2x-3)(2x)+(2x-3)(-3)=4x²-6x-6x+9=4x²-12x+9

so
5x²-(4x²-12x+9)=5x²-4x²+12x-9=x²+12x-9