Math question need help.

Question

I have a math question I’ve been having issues with and trying to figure out. I need to plug in 4f(x) to the equation

f(x)= 2x+1 and I’m looking at the text book and the answer says it’s 4f(x)= 8x+4 I’ve tried many many ways and still can’t come up with the textbook answer. Please help. It says to use the given function f to find and simplify.

Answer 1

f(x)= 2x+1

4f(x)=4(2x+1) Now use the distributive property

4f(x)=4(2x)+4(1) Simplify

4f(x)= 8x+4

Answer 2

f(4f(x)) = 2(4f(x)) + 1 = 8f(x) + 1 = 8(2x+1) + 1 = 16x + 9

Alternate method. 4f(x) = 4 (2x+1) = 8x + 4

Then f(8x+4) = 2(8x+4) + 1 = 16x +8 + 1 = 16x + 9.