(2x-6)(5x+7)=

Solution for (2x-6)(5x+7)= equation:

(2x-6)(5x+7)=

We move all terms to the left:

(2x-6)(5x+7)-()=0

We add all the numbers together, and all the variables

(2x-6)(5x+7)=0

We multiply parentheses ..

(+10x^2+14x-30x-42)=0

We get rid of parentheses

10x^2+14x-30x-42=0

We add all the numbers together, and all the variables

10x^2-16x-42=0

a = 10; b = -16; c = -42;
Δ = b2-4ac
Δ = -162-4·10·(-42)
Δ = 1936
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1936}=44$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-16)-44}{2*10}=\frac{-28}{20}
=-1+2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-16)+44}{2*10}=\frac{60}{20}
=3
$