3x^2-28x=-4x^2-5x-18

Solution for 3x^2-28x=-4x^2-5x-18 equation:

3x^2-28x=-4x^2-5x-18

We move all terms to the left:

3x^2-28x-(-4x^2-5x-18)=0

We get rid of parentheses

3x^2+4x^2+5x-28x+18=0

We add all the numbers together, and all the variables

7x^2-23x+18=0

a = 7; b = -23; c = +18;
Δ = b2-4ac
Δ = -232-4·7·18
Δ = 25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25}=5$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-23)-5}{2*7}=\frac{18}{14}
=1+2/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-23)+5}{2*7}=\frac{28}{14}
=2
$