What is the standard form of $y= (x^2-4)(2x+9) -(x+5)^2$ ?

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Answer 1 · 2016-01-28T16:49:24

$2x^3 + 8x^2 -18x - 61$

Multiply both factors:
$2x^3 + 9x^2 - 8x - 36 - (x^2 + 10x + 25)$

Distribute the negative sign through the terms in the parenthesis:
$2x^3 + 9x^2 - 8x - 36 - x^2 -10x -25$

Consolidate like terms:
$2x^3 + (9x^2 - x^2) + (-8x - 10x) + (-36 - 25)$
$2x^3 + 8x^2 -18x - 61$

What is the standard form of y= (x^2-4)(2x+9) -(x+5)^2y= (x^2-4)(2x+9) -(x+5)^2?