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

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

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

We multiply parentheses ..

(+7x^2-5x+14x-10)=0

We get rid of parentheses

7x^2-5x+14x-10=0

We add all the numbers together, and all the variables

7x^2+9x-10=0

a = 7; b = 9; c = -10;
Δ = b2-4ac
Δ = 92-4·7·(-10)
Δ = 361
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{361}=19$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-19}{2*7}=\frac{-28}{14}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+19}{2*7}=\frac{10}{14}
=5/7
$