Question

Question 5 of 10

The function f(x) = 2X is shifted 4 units left. The result is g(x). What is g(x)?
O A. g(x) = 2x + 4
O B. g(x) = 2X – 4
C. g(x) = 2x - 4
D. g(x) = 2x + 4

Answer 1

None

See below under Remark.

Explanation:

When you shift left, you think of moving in the negative direction. But it is not shown that way. You need to show what happens when you substitute a value in for x. Usually a graphing program helps to show which choice is right.

g(x) = f(x+4) = 2(x + 4)

None of the choices are this result, so we have to assume that the brackets were just omitted. The graph below shows what the answer given is the correct one.

Remark

Look at the graph carefully. The red line is f(x) = 2x

The blue line is g(x) = f(x-4) = 2(x - 4)

Notice that g(x) has shifted 4 units to the left. The x intercept has gone from 0,0 to (-4,0) and is so labeled.

If you have an answer with brackets around (x + 4) that's the one you choose. It needs the 2 outside the brackets.