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4 votes
Solve 4r2 – 9 = 91.
A:{±3}
B:{±4}
C:{±5}
D:{±6}

2 Answers

4 votes
4r² - 9 = 91
4r² = 91 + 9
4r² = 100
r² = 25
r = + / - 5

Correct option C
User Stefan Dochow
by
8.3k points
3 votes
Take the root of both sides and solve. The answer is C.
User Elyas
by
7.6k points

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