Question

Complete the square to rewrite y = x2 + 8x+ 3 in vertex form, and then identify

the minimum y-value of the function.

Please answer ASAP!!!

Answer 1

Answer: D. -13

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Work Shown:

y = x^2 + 8x + 3 is the same as y = 1x^2 + 8x + 3

It is in the form y = ax^2 + bx + c

a = 1

b = 8

c = 3

Plug the values of a and b into the formula below to get the x coordinate of the vertex (h,k)

h = -b/(2a)

h = -8/(2*1)

h = -8/2

h = -4

Plug this into the original equation to get its paired y value. This will get us the value of k

y = x^2 + 8x + 3

y = (-4)^2 + 8(-4) + 3

y = 16 - 32 + 3

y = -13

This is the smallest y output possible. Therefore it is the minimum. The minimum occurs at the vertex (h,k) = (-4, -13)

We know we are dealing with a minimum because a = 1 is positive forming a parabola that opens upward. If a < 0, then the parabola would open downward to yield a maximum.