16Hit1600
Advanced MathVery hardx-intercept after a horizontal shift

Advanced Math practice question

The function f is defined by f(x) = x² − 2x − 8, and the function g is defined by g(x) = f(x − 3). What is the smaller of the two x-intercepts of the graph of g in the xy-plane?

Answer: 1

f(x) = (x − 4)(x + 2) has x-intercepts 4 and −2. Replacing x with x − 3 shifts the graph 3 units to the right, so g has x-intercepts 7 and 1. The smaller is 1.

Common wrong answers

If you answered 7
7 is the larger intercept of g.
If you answered -5
−5 shifts the wrong way (−2 − 3).
If you answered -2
−2 is f's smaller intercept, not g's.

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