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WAEC 2023 · Paper 1 · Q48

The truth set of 8+2x−x2=08 + 2x - x^2 = 0 is {p,q}\{p, q\}. Evaluate p+qp + q.

Worked solution (try it first)
  1. Multiply by −1-1 so the x2x^2 term is positive: x2−2x−8=0x^2 - 2x - 8 = 0.
  2. Factorise: (x−4)(x+2)=0(x - 4)(x + 2) = 0, so the roots are 4 and −2-2.
  3. So p+q=4+(−2)=2p + q = 4 + (-2) = 2, option C.

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