(9x+2)(x+4)=0

Solution for (9x+2)(x+4)=0 equation:

(9x+2)(x+4)=0

We multiply parentheses ..

(+9x^2+36x+2x+8)=0

We get rid of parentheses

9x^2+36x+2x+8=0

We add all the numbers together, and all the variables

9x^2+38x+8=0

a = 9; b = 38; c = +8;
Δ = b2-4ac
Δ = 382-4·9·8
Δ = 1156
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1156}=34$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(38)-34}{2*9}=\frac{-72}{18}
=-4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(38)+34}{2*9}=\frac{-4}{18}
=-2/9
$