Question

The vertex of a quadratic function is (6, 2), and the y-

intercept of the function is (0, -70). The equation of the
function in vertex form, f(x)=a(x-h)²+k, is shown.

-70=a(0-6)²+2

What is the value of a?

-6
-2
2
6

Answer 1

a = -2

Solve for a in the equation.

-70=a(0-6)^2+2
-72=a(-6)^2
-72=a(36)
-2=a

Answer 2

-2

Explanation:

The vertex of the quadratic function is (6, 2), so h = 6 and k = 2.

The y-intercept of the function is (0, -70),

so we can substitute these values into the equation
`\sf f(x) = a(x - h)^2+ k` to get:

`\tt -70 = a(0 - 6)^2 + 2`

Solving bracket 1st.

`\tt -70 = a(-6)^2 + 2`

subtracting both side by 2

-70-2 = 36a

-72 = 36a

dividing both side by 36.

`\sf a = -(72)/(36)`

a = -2

Therefore, the value of a is -2.