7x(4x+9)=111

Solution for 7x(4x+9)=111 equation:

7x(4x+9)=111

We move all terms to the left:

7x(4x+9)-(111)=0

We multiply parentheses

28x^2+63x-111=0

a = 28; b = 63; c = -111;
Δ = b2-4ac
Δ = 632-4·28·(-111)
Δ = 16401
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(63)-\sqrt{16401}}{2*28}=\frac{-63-\sqrt{16401}}{56}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(63)+\sqrt{16401}}{2*28}=\frac{-63+\sqrt{16401}}{56}
$