(15x-2)(7x=4)+90

Solution for (15x-2)(7x=4)+90 equation:

(15x-2)(7x=4)+90

We move all terms to the left:

(15x-2)(7x-(4)+90)=0

We add all the numbers together, and all the variables

(15x-2)(7x+86)=0

We multiply parentheses ..

(+105x^2+1290x-14x-172)=0

We get rid of parentheses

105x^2+1290x-14x-172=0

We add all the numbers together, and all the variables

105x^2+1276x-172=0

a = 105; b = 1276; c = -172;
Δ = b2-4ac
Δ = 12762-4·105·(-172)
Δ = 1700416
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1700416}=1304$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1276)-1304}{2*105}=\frac{-2580}{210}
=-12+2/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1276)+1304}{2*105}=\frac{28}{210}
=2/15
$