(2x+1)(x+3)=88

Solution for (2x+1)(x+3)=88 equation:

(2x+1)(x+3)=88

We move all terms to the left:

(2x+1)(x+3)-(88)=0

We multiply parentheses ..

(+2x^2+6x+x+3)-88=0

We get rid of parentheses

2x^2+6x+x+3-88=0

We add all the numbers together, and all the variables

2x^2+7x-85=0

a = 2; b = 7; c = -85;
Δ = b2-4ac
Δ = 72-4·2·(-85)
Δ = 729
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{729}=27$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-27}{2*2}=\frac{-34}{4}
=-8+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+27}{2*2}=\frac{20}{4}
=5
$