A town launches fireworks from the top of city hall. The height h(t) of the fireworks can be calculated using the function h(t)=4.9t^2+140t+15, where t is the time in seconds. What is the maximum height?

77

step-by-step explanation:

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.