Answer:
f(x) = -3(x - 5)^2 + 4
vertex (5,4)
Step-by-step explanation:
f(x) = -3x² +30x - 71
f(x) = -3(x² +-10x) - 71
f(x) = -3(x² +-10x+5^2-5^2) - 71
f(x) = -3(x² +-10x+5^2) -3(-5^2) - 71
f(x) = -3(x² +-10x+5^2) + 4
f(x) = -3(x - 5)^2 + 4
vertex (5,4)
