Fsc Part 1 Mathematics (Complete Solution)

Q5
Solve the Following equations by factorization

x(x + 7) = (2x - 1)(x + 4)
x2 + 7x = 2x2 + 8x - x - 4
x2 + 7x = 2x2 + 7x - 4
x2 + 7x - 2x2 - 7x + 4 = 0
x2 - 2x2 + 4 = 0
-x2 + 4 = 0
x2- 4 = 0
[Multiply by -1 both sides]
x2 - 22 = 0
(x + 2)(x - 2) = 0
[∴ x2 - y2 = (x + y)(x - y) ]

Either x + 2 = 0      OR      x - 2 = 0
x = -2 x = 2
∴ Soution Set = { -2, 2 }

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