Given that P = x 2 + 4x - 2, Q = 2x - 1

MATHEMATICS
WAEC 2013

Given that P = x2 + 4x - 2, Q = 2x - 1 and Q - p = 2, find x

  • A. -2
  • B. -1
  • C. 1
  • D. 2

Correct Answer: B. -1

Explanation

P = x2 + 4x - 2, Q = 2x - 1

Q - p = 2, (2x - 1) - (x2 + 4x - 2) = 2

2x - 1 - x2 - 4x + 2 = 2

-2x - x2 + 1

-x2 - 2x - 1 = 0

x2 + 2x + 1 = 0

x2 + x + x + 1 = 0

x(x + 1) + 1(x + 1) = 0

(x + 1)(x + 1) = 0

x + 1 = 0 or x + 1 = 0

x = -1 or x = -1

x = -1



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