-4=-7t2-2t

Solution for -4=-7t2-2t equation:

-4=-7t^2-2t

We move all terms to the left:

-4-(-7t^2-2t)=0

We get rid of parentheses

7t^2+2t-4=0

a = 7; b = 2; c = -4;
Δ = b2-4ac
Δ = 22-4·7·(-4)
Δ = 116
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{116}=\sqrt{4*29}=\sqrt{4}*\sqrt{29}=2\sqrt{29}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-2\sqrt{29}}{2*7}=\frac{-2-2\sqrt{29}}{14}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+2\sqrt{29}}{2*7}=\frac{-2+2\sqrt{29}}{14}
$