(9x+45)(7x-5)=0

Solution for (9x+45)(7x-5)=0 equation:

(9x+45)(7x-5)=0

We multiply parentheses ..

(+63x^2-45x+315x-225)=0

We get rid of parentheses

63x^2-45x+315x-225=0

We add all the numbers together, and all the variables

63x^2+270x-225=0

a = 63; b = 270; c = -225;
Δ = b2-4ac
Δ = 2702-4·63·(-225)
Δ = 129600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{129600}=360$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(270)-360}{2*63}=\frac{-630}{126}
=-5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(270)+360}{2*63}=\frac{90}{126}
=5/7
$