9x^2+21x^2=34^2

Solution for 9x^2+21x^2=34^2 equation:

9x^2+21x^2=34^2

We move all terms to the left:

9x^2+21x^2-(34^2)=0

We add all the numbers together, and all the variables

30x^2-1156=0

a = 30; b = 0; c = -1156;
Δ = b2-4ac
Δ = 02-4·30·(-1156)
Δ = 138720
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:

$\sqrt{\Delta}=\sqrt{138720}=\sqrt{4624*30}=\sqrt{4624}*\sqrt{30}=68\sqrt{30}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-68\sqrt{30}}{2*30}=\frac{0-68\sqrt{30}}{60}
=-\frac{68\sqrt{30}}{60}
=-\frac{17\sqrt{30}}{15}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+68\sqrt{30}}{2*30}=\frac{0+68\sqrt{30}}{60}
=\frac{68\sqrt{30}}{60}
=\frac{17\sqrt{30}}{15}
$