Solve:
x2 + y2 = 25 y – 3x = 13 Rearrange the second equation: y = 13 + 3x Substitute the rearranged question in the first equation: x2 + (13 + 3x)2 = 25 Solve: x2 + 169 + 9x2 + 78x - 25 = 0 10x2 + 78x + 144 = 0 5x2 + 39x + 72 = 0 x = (-39 +- /1521-1440)/10 x = (-39 +-9)/10 x = -4.8, x = -3 Subsitute these two values in the rearranged equation: x = -4.8 --> y = 13 + 3*(-4.8) = -1.4 x = -3 --> y = 13 + 3*(-3) = 4
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