用代入法接下列方程1）y+2=1-x2)x+3y=43)3y-2x=13x+2y=-31/4x+1/2y=0x+2/3=y+1/44)x+y/2+2/3y=25)x+y/3+x-y/2=63x/2-2y=03(x+y)-2(x-y)=28

Question

用代入法接下列方程
1）y+2=1-x 2)x+3y=4 3)3y-2x=1
3x+2y=-3 1/4x+1/2y=0 x+2/3=y+1/4
4)x+y/2+2/3y=2 5)x+y/3+x-y/2=6
3x/2-2y=0 3(x+y)-2(x-y)=28

Answer 1

1.3 = 3x+2y = x+2(x+y)= x+2 (-1)
所以 x=5 y=-6
2.0 =1/4x+1/2y = 1/4*(x+3y)-1/4y =1-1/4 * y
y=4 x=-8
3.1 = 3y-2x = y+2(y-x) = y+2*(5/12)
y= 1/6 x==-1/4
4.2 = 4y/3+y/2+2y/3 =2.5y
y= 4/5
x=4y/3= 16/15
5.6 = 2(28-5y)+y/3-y/2
0= 50-10y-y/6
y=300/61
x=28-5y=3+25/61=3.41
x=