7.4=9.8t^2

Solution for 7.4=9.8t^2 equation:

7.4=9.8t^2

We move all terms to the left:

7.4-(9.8t^2)=0

We get rid of parentheses

-9.8t^2+7.4=0

a = -9.8; b = 0; c = +7.4;
Δ = b2-4ac
Δ = 02-4·(-9.8)·7.4
Δ = 290.08
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{290.08}}{2*-9.8}=\frac{0-\sqrt{290.08}}{-19.6}
=-\frac{\sqrt{}}{-19.6}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{290.08}}{2*-9.8}=\frac{0+\sqrt{290.08}}{-19.6}
=\frac{\sqrt{}}{-19.6}
$