3(x^2+8x-25)=0

Solution for 3(x^2+8x-25)=0 equation:

3(x^2+8x-25)=0

We multiply parentheses

3x^2+24x-75=0

a = 3; b = 24; c = -75;
Δ = b2-4ac
Δ = 242-4·3·(-75)
Δ = 1476
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1476}=\sqrt{36*41}=\sqrt{36}*\sqrt{41}=6\sqrt{41}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(24)-6\sqrt{41}}{2*3}=\frac{-24-6\sqrt{41}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(24)+6\sqrt{41}}{2*3}=\frac{-24+6\sqrt{41}}{6}
$