Solve the simultaneous equations x^2 + y^2 = 9 and y = 3x + 3
y2 = (3x + 3)2 = 9x2 + 18x + 9
x2 + 9x2 + 18x + 9 = 9
10x2 + 18x = 0 (root a: x = 0)
5x + 9 = 0 (root b: x = -1.8)
For x = 0, y = 3(0) + 3 (root a: y = 3)
For x = -1.8, y = 3(-1.8) + 3 (root b: y = -2.4)
Solutions at (0, 3) and (-1.8, -2.4)
AR
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