If f(x) = 5 - 2x, then f -1(-3) = ?
If f(x) = 5 - 2x, then f -1(-3) = ?
Answer/Solution
3
Steps/Work
Find f -1(x) and then Find f -1(- 3)
y = 5 - 2x , given
x = 5 - 2y , interchange x and y
2y = 5 - x , y = log2(5 - x) , solve for y
f -1(x) = log2(5 - x) , inverse function
f -1(- 3) = log2(5 + 3)
= log2(23) = 3
correct answer E
y = 5 - 2x , given
x = 5 - 2y , interchange x and y
2y = 5 - x , y = log2(5 - x) , solve for y
f -1(x) = log2(5 - x) , inverse function
f -1(- 3) = log2(5 + 3)
= log2(23) = 3
correct answer E