7.5x^2=30x

Solution for 7.5x^2=30x equation:

7.5x^2=30x

We move all terms to the left:

7.5x^2-(30x)=0

a = 7.5; b = -30; c = 0;
Δ = b2-4ac
Δ = -302-4·7.5·0
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-30}{2*7.5}=\frac{0}{15}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+30}{2*7.5}=\frac{60}{15}
=4
$