1、把下列方程改写成用含x的式子表示y的形式:
(1)3/2x+2y=1; (2)1/4x+7/4y=2
(3)5x-3y=x+2y (4)2(3y-3)=6x+4
2、用代入法解下列方程组:
(1){y=x+3 7x+5y=9 (2) {3s-t=5 5s+2t=15
(3) {3x+4y=16 5x-6y=33 (4) {4(x-y-1)=3(1-y)-2 x/2+y/3=2
3、用加减法解下列方程组:
(1){3u+2t=7 6u-2t=11 (2) {2a+b=3 3a+b=4
(3) {2x-5y=-3 -4x+y=-3 (4) {1/2x-3/2y=-1 2x+y=3