Rozwiąż układ równań metodą podstawiania. a) [latex] left { {{3x+y=1} atop {x=y-3}} ight. [/latex] b) [latex] left { {{2-2x=5+3x} atop {10(x-0,2y)=2}} ight. [/latex]

a) 3x+y=1 x=y-3 3 * (y-3) + y = 1 x = y - 3 3y - 9 + y = 1 x = y - 3 3y + y = 1 + 9 x = y - 3 4y = 10 x = y - 3 y = 10/4 = 2 1/2 x = 2 1/2 - 3  = -1/2 b) 2 - 2x = 5 + 3x 10 (x - 0,2y) = 2 -2x - 3x = 5 - 2 10x - 2y = 2 -5x = 3 10x - 2y = 2 x = -3/5 10 * (-3/5) - 2y = 2 x = -3/5 -6 - 2y = 2 x = -3/5 -2y = 2 + 6 x = -3/5 -2y = 8 x = -3/5 y = -4