(5x+7)(5x+2)=0

Solution for (5x+7)(5x+2)=0 equation:

(5x+7)(5x+2)=0

We multiply parentheses ..

(+25x^2+10x+35x+14)=0

We get rid of parentheses

25x^2+10x+35x+14=0

We add all the numbers together, and all the variables

25x^2+45x+14=0

a = 25; b = 45; c = +14;
Δ = b2-4ac
Δ = 452-4·25·14
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(45)-25}{2*25}=\frac{-70}{50}
=-1+2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(45)+25}{2*25}=\frac{-20}{50}
=-2/5
$