How do i do number 77? explanation and answer ! : )

Convert  to vertex form:-

y = (-4/9) (x^2 - 6x) + 12

y = -(4/9) [(x - 3)^2 - 9] + 12

y = (-4/9)(x - 3)^2 + 4 + 12

y = (-4/9)(x - 3)^2 + 16

So maximum height = 16 feet

you can first factor out the n to get n(1+5). we know that 1+5 is 6, so we just have 6n.