Zad 1 podstawiania {-2x+y=8 {x+2y-1=0 {y = 8 + 2x {x+2y-1=0 {y = 8 + 2x {x + 2(8 + 2x) - 1 = 0 {y = 8 + 2x {x + 16 + 4x - 1 = 0 {y = 8 + 2x {5x = -15 /:5 {y = 8 + 2x {x = -3 {y = 8 + 2 *(-3) {x = -3 {y = 2 {x = -3 przeciwnych wsp {-2x+y=8 {x+2y-1=0 {-2x + y = 8 /*(-2) {x + 2y = 1 {4x - 2y = -16 {x + 2y = 1 ------------------- 5x = -15 /:5 x = -3 4 * (-3) - 2y = -16 -12 - 2y = -16 -2y = -16 + 12 -2y = -4 /:(-2) y = 2 Zad 2 podstawiania {3x-2y-7=0 {x+2y+3=0 {3x-2y=7 {x+2y=-3 {3x-2y=7 {x=-3-2y {3*(-3-2y)-2y=7 {x=-3-2y {-9-6y-2y=7 {x=-3-2y {-8y=16 /(-8) {x=-3-2y {y=-2 {x=-3-2*(-2) {y=-2 {x=1 przeciwnych wsp {3x-2y=7 {x+2y=-3 ------------------- 4x=4 /:4 x=1 x+2y=-3 2y=-3-1 y=-2 Zad 3 przeciwnych wsp {7x-2y=9 {2x-y=3 /*(-2) {7x-2y=9 {-4x+2y=-6 ------------------- 3x=3 /:3 x=1 7x-2y=9 7-2y=9 -2y=2 /:(-2). y=-1 podstawiania {7x-2y=9 {2x-y=3 {7x-2y=9 {y=-3+2x {7x-2(-3+2x)=9 {y=-3+2x {7x+6-4x=9 {y=-3+2x {3x=9-6 /:3 {y=-3+2x {x=1 {y=-3+2*1 {x=1 {y = -1
