0=-4.9t^2+9t+700

Solution for 0=-4.9t^2+9t+700 equation:

0=-4.9t^2+9t+700

We move all terms to the left:

0-(-4.9t^2+9t+700)=0

We add all the numbers together, and all the variables

-(-4.9t^2+9t+700)=0

We get rid of parentheses

4.9t^2-9t-700=0

a = 4.9; b = -9; c = -700;
Δ = b2-4ac
Δ = -92-4·4.9·(-700)
Δ = 13801
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:

$\sqrt{\Delta}=\sqrt{13801}=\sqrt{1*13801}=\sqrt{1}*\sqrt{13801}=1\sqrt{13801}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-1\sqrt{13801}}{2*4.9}=\frac{9-1\sqrt{13801}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+1\sqrt{13801}}{2*4.9}=\frac{9+1\sqrt{13801}}{9.8}
$