Answer:
Step-by-step explanation:
to get the maximum value of y which represents the number of mangoes per year, you need to get the derivative of the equation.
[tex]y=-20x^{2} +2800x[/tex]
[tex]y'=-40x+2800[/tex]
for maximum value of y, y' should be zero.
[tex]0=-40x+2800\\40x=2800\\x=70[/tex]
ibig sabihin 70 trees ang dapat na itanim para maximum yung mangoes na maproduce. hope this helps.