3(r+7)6r=48

Solution for 3(r+7)6r=48 equation:

3(r+7)6r=48

We move all terms to the left:

3(r+7)6r-(48)=0

We multiply parentheses

18r^2+126r-48=0

a = 18; b = 126; c = -48;
Δ = b2-4ac
Δ = 1262-4·18·(-48)
Δ = 19332
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{19332}=\sqrt{36*537}=\sqrt{36}*\sqrt{537}=6\sqrt{537}$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(126)-6\sqrt{537}}{2*18}=\frac{-126-6\sqrt{537}}{36}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(126)+6\sqrt{537}}{2*18}=\frac{-126+6\sqrt{537}}{36}
$