#1**+1 **

Use the quadratic formula to solve for r. Then sub both values of r into your equation and see which one gives a higher value.

Guest Jul 31, 2019

#2**0 **

This is a dome shaped parabola (due to the negative coefficient of the x^2 term)

the r value at the max point will be given by -b /2a where a =-5 b = 40 sooooooo r = ?

Once you FIND this r value, sub in to the equation to find the max value of the expression.... You CAN do it !

ElectricPavlov Jul 31, 2019