8a2-17a-70=-4

Solution for 8a2-17a-70=-4 equation:

8a^2-17a-70=-4

We move all terms to the left:

8a^2-17a-70-(-4)=0

We add all the numbers together, and all the variables

8a^2-17a-66=0

a = 8; b = -17; c = -66;
Δ = b2-4ac
Δ = -172-4·8·(-66)
Δ = 2401
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2401}=49$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-17)-49}{2*8}=\frac{-32}{16}
=-2
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-17)+49}{2*8}=\frac{66}{16}
=4+1/8
$