Solve the simultaneous equations: (1) x^2 + y^2 = 25 and (2) y - 3x = 13

Sub (2) y = 13 + 3x into (1)x^2 + (13 + 3x)^2 = 25x^2 + 169 + 39x + 39x + 9x^2 = 2510x^2 + 78x + 144 = 05x^2 + 39x + 72 = 0 (/2)572 = 360 - need ab=360 such that a+b=39a = 24 b = 155x^2 + 24x + 15x + 72 = 0x(5x + 24) + 3(5x + 24) = 0 [take out the gcf, greatest common factor](x + 3)(5x + 24) = 0x = -3x = -24/5y = 13 + 3(-3) = 4y = 13 + 3(-24/5) = -7/5