Question

How do i solve this?

Answer 1

Answer: x = 1, 7, vertex is at (4, -9)

Explanation:

To find the x-intercepts, we will factor and solve. Finding the x-intercepts is the same as finding the solutions, where f(x) = 0. -7 and -1 multiply to 7, and -7 + -1 = -8.

y = x² - 8x + 7

y = (x - 7)(x - 1)

x = 7 x = 1

Next, we can use this equation to help us find the x-value of the vertex.

`\displaystyle (-b)/(2a) =(8)/(2(1)) =(8)/(2) =4`

Then, we will substitute this value back into the equation to solve for the y-value.

y = x² - 8x + 7

y = (4)² - 8(4) + 7

y = -9

The vertex is at (4, -9)