Algebra 8

2 marks · Normal

Let f(x) = 2x + 3. State the domain and the range of f when the domain is {−2, 0, 4}.

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Domain: {−2, 0, 4}; Range: {−1, 3, 11}

Also accept: Domain: {−2, 0, 4} and Range: {−1, 3, 11}; {−2, 0, 4}; {−1, 3, 11}

Common mistakes: Calculating f incorrectly; not matching range to domain

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Marking points

B1 · 1 mark · States correct domain: {−2, 0, 4}

B2 · 1 mark · Correctly finds range: {−1, 3, 11}

Worked solution

f(−2) = 2×(−2) + 3 = −4 + 3 = −1

f(0) = 2×0 + 3 = 0 + 3 = 3

f(4) = 2×4 + 3 = 8 + 3 = 11