Algebra 1 Flight with Completing the Square

Question

The height of a ball thrown from the top of a platform can be modeled by the equation f(x) = -16x^2 + 64x -34, where f(x) is the height, in feet, x seconds after the ball was thrown.

1. Complete the square to write the function in vertex form.

2. Find and interpret the coordinates of the vertex and the maximum of the function.

Answer 1

I'll complete the square for you; you answer the rest of the questions.

16x² - 64x - 34 = (4x - 8)² - 98 = 16(x-2)² - 98

But the original equation has a negative leading coefficient: s(x) = -16(x-2)² + 98

Yup, I missed a sign!

16x² - 64x +34 = (4x-8)² + 30 is correct, i.e. s(x)=-16(x-2)² +30

Do you see where I missed the sign! You should have been able to find my error.

SOrry, I made this error.