3(2+5)=7x2+15-3x

Solution for 3(2+5)=7x2+15-3x equation:

3(2+5)=7x^2+15-3x

We move all terms to the left:

3(2+5)-(7x^2+15-3x)=0

We add all the numbers together, and all the variables

-(7x^2+15-3x)+37=0

We get rid of parentheses

-7x^2+3x-15+37=0

We add all the numbers together, and all the variables

-7x^2+3x+22=0

a = -7; b = 3; c = +22;
Δ = b2-4ac
Δ = 32-4·(-7)·22
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{-(3)-25}{2*-7}=\frac{-28}{-14}
=+2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+25}{2*-7}=\frac{22}{-14}
=-1+4/7
$