x(15x-x)=49

Solution for x(15x-x)=49 equation:

x(15x-x)=49

We move all terms to the left:

x(15x-x)-(49)=0

We add all the numbers together, and all the variables

x(+14x)-49=0

We multiply parentheses

14x^2-49=0

a = 14; b = 0; c = -49;
Δ = b2-4ac
Δ = 02-4·14·(-49)
Δ = 2744
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:

$\sqrt{\Delta}=\sqrt{2744}=\sqrt{196*14}=\sqrt{196}*\sqrt{14}=14\sqrt{14}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-14\sqrt{14}}{2*14}=\frac{0-14\sqrt{14}}{28}
=-\frac{14\sqrt{14}}{28}
=-\frac{\sqrt{14}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+14\sqrt{14}}{2*14}=\frac{0+14\sqrt{14}}{28}
=\frac{14\sqrt{14}}{28}
=\frac{\sqrt{14}}{2}
$