X(15-7x)=0

Solution for X(15-7x)=0 equation:

X(15-7X)=0

We add all the numbers together, and all the variables

X(-7X+15)=0

We multiply parentheses

-7X^2+15X=0

a = -7; b = 15; c = 0;
Δ = b2-4ac
Δ = 152-4·(-7)·0
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-15}{2*-7}=\frac{-30}{-14}
=2+1/7
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+15}{2*-7}=\frac{0}{-14}
=0
$