(4x+8)(2x+3)=70

Solution for (4x+8)(2x+3)=70 equation:

(4x+8)(2x+3)=70

We move all terms to the left:

(4x+8)(2x+3)-(70)=0

We multiply parentheses ..

(+8x^2+12x+16x+24)-70=0

We get rid of parentheses

8x^2+12x+16x+24-70=0

We add all the numbers together, and all the variables

8x^2+28x-46=0

a = 8; b = 28; c = -46;
Δ = b2-4ac
Δ = 282-4·8·(-46)
Δ = 2256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{2256}=\sqrt{16*141}=\sqrt{16}*\sqrt{141}=4\sqrt{141}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(28)-4\sqrt{141}}{2*8}=\frac{-28-4\sqrt{141}}{16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(28)+4\sqrt{141}}{2*8}=\frac{-28+4\sqrt{141}}{16}
$