Question

The sum of a positive number 'A' and its square is 72. Find the value of (A2 - 7

  • A .
A 14 Correct Answer Incorrect Answer
B 8 Correct Answer Incorrect Answer
C 18 Correct Answer Incorrect Answer
D 56 Correct Answer Incorrect Answer

Solution

ATQ; A + A2 = 72 Or, A2 + A - 72 = 0 Or, A2 + 9A - 8A - 72 = 0 Or, (A + 9)(A - 8) = 0 So, A = 8 or A = -9 Since, 'A' is positive. So, required value = 82 - 8 × 7 = 64 - 56 = 8

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