Rozwiąż układy równań: a) {x-y=2 {jedna druga x - 1 = jedna czwarta y   b) {5x-1=3y {1,6y-2=4-2x   c) {-x-y=2 {2(3x+y)=-20   d) {4x+3y=54 {jedna trzecia x =4(1+ jedna ósma y )  

a] x-y=2 ½x-1=¼y/×4   x=y+2 2(y+2)-4=y   x=y+2 2y+4-4=y   2y-y=0 y=0 x=0+2 x=2 b] 5x-1=3y 1,6y-2=4-2x   5x=1+3y 2x+1,6y=4+2   x=⅕+⅗y 2(⅕+⅗y)+1⅗y=6   ⅖+⁶/₅y+⁸/₅y=6/×5 x=⅕+⅗y   2+6y+8y=30   14y=30-2 x=⅕+⅗y   y=28:14=2 x=⅕+⅗×2=⅕+⁶/₅=1⅖ c] -x-y=2 2(3x+y)=-20   x=-y-2 6(-y-2)+2y=-20   x=-y-2 -6y-12+2y=-20   x=-y-2 -4y=-20+12   y=-8:-4=2 x=-2-2=-4 d] 4x+3y=54 ⅓x=4(1+⅛y)   4x+3y=54 ⅓x=4+½y   4x+3y=54 ⅓x-½y=4/×3   x-1,5y=12 x=12+1,5y   4(12+1,5y)+3y=54 48+6y+3y=54 9y=54-48 y=6:9=⅔   x=12+³/₂×⅔=13