Algebra · real student question

The function f(x) = |x - 4| - 3 is translated 6 units up and 2 units right. Write the equation of the new function.

Question

The function f(x)=x43f(x)=|x-4|-3 is translated 66 units up and 22 units right. Write the equation of the translated function.

Step-by-step solution

  1. Locate the starting vertex. For f(x)=xh+kf(x)=|x-h|+k the corner sits at (h,k)(h,k). Reading f(x)=x43f(x)=|x-4|-3 gives h=4h=4 and k=3k=-3, so the vertex is at

    (4,3)(4,-3)

    Tracking the vertex is the fastest way to keep translations straight, because the V-shape itself never changes — only where its corner sits.

  2. Apply the horizontal shift by replacing xx with x2x-2. Moving a graph 22 units right means every input must be 22 larger to produce the same output, so the substitution subtracts:

    f(x2)=(x2)43=x63f(x-2)=\left|(x-2)-4\right|-3=|x-6|-3

    The sign feels backwards to most students — right shifts subtract inside — which is exactly why it is worth doing as a substitution rather than from memory.

  3. Apply the vertical shift by adding outside. Moving 66 units up adds 66 to the whole output:

    x63+6=x6+3|x-6|-3+6=|x-6|+3

    Vertical shifts behave the intuitive way: up means ++.

  4. State the transformed function and its vertex.

    f(x)=x6+3,vertex (6,3)f(x)=|x-6|+3,\qquad \text{vertex }(6,3)

    The vertex moved from (4,3)(4,-3) to (6,3)(6,3): right 22, up 66 — precisely the instructions, which is the built-in check.

  5. Verify with a test point. On the original graph, f(4)=443=3f(4)=|4-4|-3=-3 (the corner). The corresponding point after moving right 22 and up 66 should be (6,3)(6,3), and the new formula gives 66+3=3  |6-6|+3=3\;\checkmark. Checking one more: original f(0)=43=1f(0)=|{-4}|-3=1 maps to (2,7)(2,7), and the new function gives 26+3=4+3=7  |2-6|+3=4+3=7\;\checkmark.

Answer

f(x)=x6+3f(x)=|x-6|+3

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