7x(4x-18)=16

Solution for 7x(4x-18)=16 equation:

7x(4x-18)=16

We move all terms to the left:

7x(4x-18)-(16)=0

We multiply parentheses

28x^2-126x-16=0

a = 28; b = -126; c = -16;
Δ = b2-4ac
Δ = -1262-4·28·(-16)
Δ = 17668
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:

$\sqrt{\Delta}=\sqrt{17668}=\sqrt{4*4417}=\sqrt{4}*\sqrt{4417}=2\sqrt{4417}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-126)-2\sqrt{4417}}{2*28}=\frac{126-2\sqrt{4417}}{56}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-126)+2\sqrt{4417}}{2*28}=\frac{126+2\sqrt{4417}}{56}
$