Question 1073930
By your equation;
-16t²+180t=280
16t²-180t+280=0
4t²-45t+70=0
Using the quadratic formula, we get two roots of  9.38540223912 and 1.86459776088, or 9.4 and 1.9 seconds after launch. &#9786;&#9786;&#9786;&#9786;