X^2+7.5x=0

Solution for X^2+7.5x=0 equation:

X^2+7.5X=0

a = 1; b = 7.5; c = 0;
Δ = b2-4ac
Δ = 7.52-4·1·0
Δ = 56.25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7.5)-\sqrt{56.25}}{2*1}=\frac{-7.5-\sqrt{56.25}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7.5)+\sqrt{56.25}}{2*1}=\frac{-7.5+\sqrt{56.25}}{2}
$