Question

Which Function is the result of translating

F(x) = x² - 4x +3 with a vertical-Stretch by a
Factor of a and a reflection across the
y-axis?
A, y=-2x² - 8x +6
B.y = 2x² -8x + 6
C, y = 2X² + 8x+6
D, y=2X² +4x+6.

Answer 1

C. y = 2x² +8x +6

Explanation:

Reflecting f(x) across the y-axis changes the sign of x, so the new function is ...

f(-x)

Vertical scaling by a factor of "a" multiplies the function value by "a", so the new function is ...

a·f(x)

Doing both gives you ...

y = a·f(-x)

y = ax² +4ax +3a

None of the answer choices look like this. However, they match this if a=2:

y = 2x² +8x +6