Question

What is the vertex of the function f(x)=2x^2+4x-16?

Answer 1

(-2,4) ?

Answer 2

standard form

y = a(x-h)^2+k

y= 2x^2 + 4x - 16 move the 16 to the other side

y + 16 = 2x^2 + 4x factor out a 2 from the right side.

y + 16 = 2(x^2 + 2x) complete the square

y + 16 + 2( 1 ) = 2( x^2 +2x + 1) simplify.

y + 18 = 2(x + 1)^2

y = 2(x + 1)^2 - 18 put it back in standard form.

y = 2( x - (-1))^2 + (-18)

Answer 3

Refer to the attached Mathematica calculation.

Answer 4

Am i wrong? :\

Answer 5

Oh i see.

Answer 6

WELL!! we got the same thing, lol. (-1,-18) for the vertex. Thanks @robtobey :)