(7-2x)(10-2x)=0

Solution for (7-2x)(10-2x)=0 equation:

(7-2x)(10-2x)=0

We add all the numbers together, and all the variables

(-2x+7)(-2x+10)=0

We multiply parentheses ..

(+4x^2-20x-14x+70)=0

We get rid of parentheses

4x^2-20x-14x+70=0

We add all the numbers together, and all the variables

4x^2-34x+70=0

a = 4; b = -34; c = +70;
Δ = b2-4ac
Δ = -342-4·4·70
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-34)-6}{2*4}=\frac{28}{8}
=3+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-34)+6}{2*4}=\frac{40}{8}
=5
$