68=(3a^2)-5a

Solution for 68=(3a^2)-5a equation:

68=(3a^2)-5a

We move all terms to the left:

68-((3a^2)-5a)=0

We get rid of parentheses

-3a^2+5a+68=0

a = -3; b = 5; c = +68;
Δ = b2-4ac
Δ = 52-4·(-3)·68
Δ = 841
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{841}=29$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-29}{2*-3}=\frac{-34}{-6}
=5+2/3
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+29}{2*-3}=\frac{24}{-6}
=-4
$