Question

Help??

Which of the following equations represents a parabola that opens up and has a vertex with a positive x-value?

A) y=-x^2+8x-15
B) y=2x^2-16x+38
C) y=2x^2+16x+24
D) y=-4x^2-14x-12

Answer 1

A parabola that opens up have a positive x∧2
So we know it can't be a or d so we are left with b or c
To find the x-value of the vertex, use the formula -b/2a
So the answer is B

Answer 2

Answer:

option B

Step-by-step explanation:

Find equations represents a parabola that opens up and has a vertex with a positive x-value

When leading term is positive then the parabola opens up.

When leading term is negative then the parabola opens down.

option A  and D have leading term negative. so parabola opens down.

B)$y=2x^2-16x+38$

Now we find out the vertex using formula $x=\frac{-b}{2a}$

a=2 and b = -16

$x=\frac{-b}{2a}=\frac{16}{2(2)}=4$

C) $y=2x^2+16x+24$

a=2 and b = 16

$x=\frac{-b}{2a}=\frac{-16}{2(2)}=-4$

So option B represents a parabola that opens up and has a vertex with a positive x-value