Solve the simultaneous equations: 4x + 7y = 1, 3x + 10y = 15.
4x + 7y = 1 1. 3x + 10y = 15 2. 1. x 3 (4x x 3) + (7y x 3) = 1 x 3 12x + 21y = 3 3. 2. x 4 (3x x 4) + (10y x 4) = 15 x 4 12x + 40y = 60 4. 4. - 3. (12x - 12x) + (40y - 21y) = 60 - 3 19y = 57 y = 57/19 y = 3 Sub y into 2. 3x + 10(3) = 15 3x + 30 = 15 3x = 15 - 30 3x = -15 x = -15/3 x = -5 y = 3, x = -5
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