What is the standard form of $y= (-2x+5)^3-(2x+2)^2$ ?

Question

1554 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-11-16T12:19:20

This is a form of:
$y=ax^3+bx^2+cx+d$

$y=(-2x+5)^3-(2x+2)^2$
$=> y=(-2x+5)*(-2x+5)*(-2x+5)-(2x+2)*(2x+2)$
$=> y=(4x^2-20x+25)*(-2x+5)-(4x^2+8x+4)$

$(4x^2-20x+25)*(-2x+5)=-8x^3+20x^2+40x^2-100x-50x+125$
$= -8x^3+60x^2-150x+125$

--

$-(4x^2+8x+4)=-4x^2-8x-4$

--

$y=(-2x+5)^3-(2x+2)^2=...= -8x^3+60x^2-150x+125-4x^2-8x-4$
$=> y=-8x^3+56x^2-158x+121$

This is a form of:
$y=ax^3+bx^2+cx+d$
for
$a=-8 , b=56 , c=-158 , d=121$

What is the standard form of y= (-2x+5)^3-(2x+2)^2 y= (-2x+5)^3-(2x+2)^2?