135=3h(h+4)

Solution for 135=3h(h+4) equation:

135=3h(h+4)

We move all terms to the left:

135-(3h(h+4))=0


We calculate terms in parentheses: -(3h(h+4)), so:

3h(h+4)

We multiply parentheses

3h^2+12h

Back to the equation:

-(3h^2+12h)


We get rid of parentheses

-3h^2-12h+135=0

a = -3; b = -12; c = +135;
Δ = b2-4ac
Δ = -122-4·(-3)·135
Δ = 1764
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1764}=42$
$h_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-42}{2*-3}=\frac{-30}{-6}
=+5
$
$h_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+42}{2*-3}=\frac{54}{-6}
=-9
$