Question

Write the vertex and indicate if the graph opens up or down.

y = 2x² + 8x + 3


A. (-2, - 5) up

B. (-2, 5) up

C. (-2, -5) down

D. (2, 5) down

Answer 1

The answer is A,) (-2,-5) because I just did it in my CASIO calculator

Answer 2

complee the square to get into for
y=a(x-h)^2+k
(h,k) is vertex
if a is positive, it opens up
if a is negative, it opens down

so
y=2x²+8x+3
y=(2x²+8x)+3
y=2(x²+4x)+3
take 1/2 of 4 and square it
4/2=2, 2²=4
ad negative and positive of it inside
y=2(x²+4x+4-4)+3
factor pefect square
y=2((x+2)²-4)+3
distribute
y=2(x+2)²-8+3
y=2(x+2)²-5
y=2(x-(-2))²+(-5)
vertex isi (-2,-5)
2 is positive so it opens up


(-2,-5) up
A is answer