(1){x+2y=4①,2x-y=3②(2){3x-4y=19①,x+2y=3②(3){3x-2y=7①,2分之x+3-y=0②(4){x-2y=1①,2x+3y=16②(5){ 4s+3t=5①,2s-t=-5②(6){2x+5y=12①,2x+3y=6②(7){2a-3b=4①,a/2+b/2=1②(8){x-2=2(y-1)①,2(x-2)+y-1=5②

问题描述:

(1){x+2y=4①,2x-y=3②
(2){3x-4y=19①,x+2y=3②
(3){3x-2y=7①,2分之x+3-y=0②
(4){x-2y=1①,2x+3y=16②
(5){ 4s+3t=5①,2s-t=-5②
(6){2x+5y=12①,2x+3y=6②
(7){2a-3b=4①,a/2+b/2=1②
(8){x-2=2(y-1)①,2(x-2)+y-1=5②

(1)x+2y=4①,2x-y=3②,②-2×①得:-5y=-5;y=1,代入①,解得x=4-2=2(2)3x-4y=19①,x+2y=3②;3×②-①得:10y=-10;y=-1;代入②,解得x=3+2=5(3)3x-2y=7①,2分之x+3-y=0②②×2得:x-2y=-6;③③×3-①得:-4y=-25...