How do you solve 4x^2+28x-32=0 by factoring?

Refer to explanation

Explanation:

We can write it as follows

4x^2+28x-32=0=>4*(x^2+7x-8)=0=>x^2+7x-8=0=>x^2+8x-x-8=0= x^2-x+8(x-1)=0=>x(x-1)+8(x-1)=0=>(x-1)*(x+8)=0=> x=1 or x=-8

Sep 30, 2015

Solve $f \left(x\right) = 4 {x}^{2} + 28 x - 32 = 0$

Ans: 1 and -8

Explanation:

$f \left(x\right) = 4 y = 4 \left({x}^{2} + 7 x - 8\right) = 0$. Solve y = 0.
Because (a + b + c = 0), use Shortcut. The 2 real roost are: x = 1 and $x = \frac{c}{a} = - 8$

REMINDER of the SHORTCUT.
1. When (a + b + c = 0), the 2 real roots are: x = 1 and $x = \frac{c}{a}$
2. When (a - b + c = 0), the 2 real roots are x = - 1 and $x = - \frac{c}{a}$