二元线性方程组的简单实问题
3x+y=34
2.9x+4y=35
8x+3y=30
3.7x+2y=52
7x+4y=62
4.4x+6y=54
9x+2y=87
5.2x+y=7
2x+5y=19
6.x+2y=21
3x+5y=56
7.5x+7y=52
5x+2y=22
8.5x+5y=65
7x+7y=203
9.8x+4y=56
x+4y=21
10.5x+7y=41
5x+8y=44
11.7x+5y=54
3x+4y=38
12.x+8y=15
4x+y=29
13.3x+6y=24
9x+5y=46
14.9x+2y=62
4x+3y=36
15.9x+4y=46
7x+4y=42
16.9x+7y=135
4x+y=41
17.3x+8y=51
x+6y=27
18.9x+3y=99
4x+7y=95
19.9x+2y=38
3x+6y=18
20.5倍+5y=45
7x+9y=69
21.8x+2y=28
7x+8y=62
22.x+6y=14
3x+3y=27
23.7x+4y=67
2x+8y=26
24.5x+4y=52
7x+6y=74
25.7x+y=9
4x+6y=16
26.6x+6y=48
6x+3y=42
27.8x+2y=16
7x+y=11
28.4倍+9y=77
8x+6y=94
29.6x+8y=68
7x+6y=66
30.2x+2y=22
7x+2y=47
回答
1.2x+9y=81
3x+y=34
2x+9(34-3x)=81
27x-2x=306-81
25x=225
x=9
y=34-3x=34-3*9=7
x=9
y=7
2.9x+4y=35
8x+3y=30
27x+12y=105
32x+12y=120
32x-27x=120-105
5x=15
x=3
y=(30-8x)/3=(30-8*3)/3=2
x=3
y=2
3.7x+2y=52
7x+4y=62
4y-2y=62-52
2y=10
y=5
x=(52-2y)/7=(52-2*5)/7=6
x=6
y=5
4.4x+6y=54
9x+2y=87
4x+6y=54
27x+6y=261
27x-4x=261-54
23x=207
x=9
y=(87-9x)/2=(87-9*9)/2=3
x=9
y=3
5.2x+y=7
2x+5y=19
5y-y=19-7
4y=12
y=3
x=(7-y)/2=(7-3)/2=2
x=3
y=2
6.x+2y=21
3x+5y=56
3x+6y=63
3x+5y=56
6y-5y=63-56
y=7
x=21-2y=21-2*7=7
x=7
y=7
7.5x+7y=52
5x+2y=22
7y-2y=52-22
5y=30
y=6
x=(22-2y)/5=(22-2*6)/5=2
x=2
y=6
8.5x+5y=65
7x+7y=203
x+y=13
x+y=29
9.8x+4y=56
x+4y=21
8(21-4y)+4y=56
32y-4y=168-56
28y=112
y=4
x=21-4y=21-4*4=5
x=5
y=4
10.5x+7y=41
5x+8y=44
8y-7y=44-41
y=3
x =(41-7y)/5 =(41-7 * 3)/5 = 4
x=4
y=3
11.7x+5y=54
3x+4y=38
28x+20y=216
15x+20y=190
28x-15x=26
x=2
y=(38-3x)/4=(38-3*2)/4=8
x=2
y=8
12.x+8y=15
4x+y=29
4x+32y=60
4x+y=29
32y-y=31
y=1
x=15-8y=15-8=7
x=7
y=1
13.3x+6y=24
9x+5y=46
x+2y=8
9x+5y=46
9(8-2y)+5y=46
18y-5y=72-46
13y=26
y=2
x=8-2y=8-2*2=4
x=4
y=2
14.9x+2y=62
4x+3y=36
27x+6y=186
8x+6y=72
27x-8x=186-72
19x=114
x=6
y=(62-9x)/2=(62-9*6)/2=4
x=6
y=4
15.9x+4y=46
7x+4y=42
9x-7x=46-42
2x=4
x=2
y=(42-7x)/4=(42-7*2)/4=7
x=2
y=7
16.9x+7y=135
4x+y=41
9x+7(41-4x)=135
28x-9x=287-135
19x=152
x=8
y=41-4x=41-4*8=9
x=8
y=9
17.3x+8y=51
x+6y=27
3(27-6y)+8y=51
18y-8y=81-51
10y=30
y=3
x=27-6y=27-6*3=9
x=9
y=3
18.9x+3y=99
4x+7y=95
63x+21y=693
12x+21y=285
63x-12x=693-285
51x=408
x=8
y=(99-9x)/3=(99-9*8)/3=9
x=8
y=9
19.9x+2y=38
3x+6y=18
9x+2y=38
9x+18y=54
18y-2y=54-38
16y=16
y=1
x =(18-6y)/3 =(18-6 * 1)/3 = 4
x=4
y=1
20.5倍+5y=45
7x+9y=69
x+y=9
7x+9y=69
7x+7y=63
9y-7y=69-63
2y=6
y=3
x=9-y=9-3=6
x=6
y=3
21.8x+2y=28
7x+8y=62
4x+y=14
7x+8y=62
7x+8(14-4x)=62
32x-7x=112-62
25x=50
x=2
y=14-4x=14-4*2=6
x=2
y=6
22.x+6y=14
3x+3y=27
3x+18y=42
3x+3y=27
18y-3y=15
y=1
x = 14-6y = 14-6 * 1 = 8
x=8
y=1
23.7x+4y=67
2x+8y=26
7x+4y=67
x+4y=13
7x-x=67-13
6x=54
x=9
y =(13-x)/4 =(13-9)/4 = 1
x=9
y=1
24.5x+4y=52
7x+6y=74
30x+24y=312
28x+24y=296
30x-28x=312-296
2x=16
x=8
y=(52-5x)/4=(52-5*8)/4=3
x=8
y=3
25.7x+y=9
4x+6y=16
42x+6y=54
4x+6y=16
42x-4x=54-16
38x=38
x=1
y=9-7x=9-7*1=2
x=1
y=2
26.6x+6y=48
6x+3y=42
6y-3y=48-42
3y=6
y=2
x=(42-3y)/6=(42-3*2)/6=6
x=6
y=2
27.8x+2y=16
7x+y=11
8x+2y=16
14x+2y=22
14x-8x=22-16
6x=6
x=1
y = 11-7x = 11-7 * 1 = 4
x=1
y=4
28.4倍+9y=77
8x+6y=94
8x+18y=154
8x+6y=94
18y-6y=154-94
12y=60
y=5
x=(77-9y)/4=(77-9*5)/4=8
x=8
y=5
29.6x+8y=68
7x+6y=66
42x+56y=476
42x+36y=396
56y-36y=476-396
20y=80
y=4
x=(68-8y)/6=(68-8*4)/6=6
x=6
y=4
30.2x+2y=22
7x+2y=47
7x-2x=47-22
5x=25
x=5
y = 11-x = 11-5 = 6
x=5
y=6