Fsc Part 1 Mathematics (Complete Solution)

Q10
Solve the following equations by completing the square

x2 + 4x - 1085 = 0
x2 + 4x = 1085
x2 + 2(2)x = 1085
Add (2)2 to both sides
x2 + 2(2)x + (2)2 = 1085 + (2)2
x2 + 2(2)x + (2)2 = 1085 + 4
(x + 2)2 = 1089
(x + 2)2 = (33)2
Taking Square Root on both sides

(x + 2)2 = ± (33)2
x + 2 = ±33
x = ±33 - 2

Either     x = 33 - 2      OR      x = -33 - 2
x = 31      OR      x = -35



The Solution Set of the equation is {-35, 31}

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