(26+5)x2-15=5

Solution for (26+5)x2-15=5 equation:

(26+5)x2-15=5

We move all terms to the left:

(26+5)x2-15-(5)=0

We add all the numbers together, and all the variables

31x2-15-5=0

We add all the numbers together, and all the variables

31x^2-20=0

a = 31; b = 0; c = -20;
Δ = b2-4ac
Δ = 02-4·31·(-20)
Δ = 2480
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:

$\sqrt{\Delta}=\sqrt{2480}=\sqrt{16*155}=\sqrt{16}*\sqrt{155}=4\sqrt{155}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{155}}{2*31}=\frac{0-4\sqrt{155}}{62}
=-\frac{4\sqrt{155}}{62}
=-\frac{2\sqrt{155}}{31}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{155}}{2*31}=\frac{0+4\sqrt{155}}{62}
=\frac{4\sqrt{155}}{62}
=\frac{2\sqrt{155}}{31}
$