Solve the equation; 3x - 2y = 7, x + 2y = -3

Mathematics

WAEC 2011

A. x = 1, y = -2
B. x = 1, y = 3
C. x = -2, y = -1
D. x = 4, y = -3

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Correct Answer: Option A

Explanation

3x - 2y = 7; Solve by elimination method

x + 2y = -3

3x - 2y = 7.....(i)

-3x + 6y = -9.....(ii)

-8y = 16

y = \(\frac{16}{-8} = -2\)

Put y = -2 into equation (i); 3x - 2y = 7

3x - 2(-2) = 7

3x + 4 = 7

3x = 7 - 4

3x = 3

x = \(\frac{3}{3}\) = 1

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