3=-4.9t^2+30t+0.03

Solution for 3=-4.9t^2+30t+0.03 equation:

3=-4.9t^2+30t+0.03

We move all terms to the left:

3-(-4.9t^2+30t+0.03)=0

We get rid of parentheses

4.9t^2-30t-0.03+3=0

We add all the numbers together, and all the variables

4.9t^2-30t+2.97=0

a = 4.9; b = -30; c = +2.97;
Δ = b2-4ac
Δ = -302-4·4.9·2.97
Δ = 841.788
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{-(-30)-\sqrt{841.788}}{2*4.9}=\frac{30-\sqrt{841.788}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+\sqrt{841.788}}{2*4.9}=\frac{30+\sqrt{841.788}}{9.8}
$