Question

Which statements describe transformations performed in f (x) = x^2 to create g (x) = 2x^2 + 5? select all that apply.

a. a vertical stretch with a scale factor of .5
b. a translation of 5 units to the right.
c. a translation of 5 units up.
d. a vertical stretch with a scale factor of 2.

Answer 1

The statements describe transformations performed in f(x) to create g(x) are:

a translation of 5 units up ⇒ c

a vertical stretch with a scale factor of 2 ⇒ d

Explanation:

• If f(x) stretched vertically by a scale factor m, then its image g(x) = m·f(x)

• If f(x) translated vertically k units, then its image h(x) = f(x) + k

Let us use these rule to solve the question

∵ f(x) = x²

∵ g(x) is created from f(x) by some transformation

∵ g(x) = 2x² + 5

→ Substitute x² by f(x) in g(x)

∴ g(x) = 2f(x) + 5

→ Compare it with the rules above

∴ m = 2 and k = 5

→ That means f(x) is stretched vertically and translated up

∴ f(x) is stretched vertically by scal factor 2

∴ f(x) is translated 5 uints up

The statements describe transformations performed in f(x) to create g(x) are:

• a translation of 5 units up

• a vertical stretch with a scale factor of 2