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A GMAT PS question asks: 'What is x if 3x + 5 = 23?' Options: 4, 5, 6, 7. The fastest approach is:
ASet up algebra step by step to find x = 6
BEstimate using twenty three over three at 7.7
CBacksolve by trying x = 6 and checking 3(6)+5 = 23
DSkip the question entirely and return at the end
Answer & Solution
Correct answer: C. Backsolve by trying x = 6 and checking 3(6)+5 = 23
Backsolving by substitution: x = 6 gives 3(6)+5 = 23 ✓. Often faster than algebra for clean numerical options. The GMAT shortcut.
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