15x^2+10x=280

Solution for 15x^2+10x=280 equation:

15x^2+10x=280

We move all terms to the left:

15x^2+10x-(280)=0

a = 15; b = 10; c = -280;
Δ = b2-4ac
Δ = 102-4·15·(-280)
Δ = 16900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16900}=130$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-130}{2*15}=\frac{-140}{30}
=-4+2/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+130}{2*15}=\frac{120}{30}
=4
$