Question 1098543
they have essentially told you what the equation is that will solve this poblem for you.


what's left for you is to graph the equation and find out when the value of y is equal to 80.


the following graph does that.


you graph y = -32x^2/150^2 + x and you graph y = 80.


the intersection of those two equations is your solution.


my graph is shown below:


<img src="http://theo.x10hosting.com/2017/102201.jpg" alt="$$$" >


the graphing software i use is at <a href = "https://www.desmos.com/calculator" target = "_blank">https://www.desmos.com/calculator</a>


their solution is rounded to three decimal points.


just round to 1 decimal point and you'll see that the solution is what you are looking for.