1.2x + 9y = 81 3x + y = 34

2019-04-14 19:32
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6
x + 2 y = 21(1)3 x + 5 y = 56(2)3(1) - (2)3 x + 6 y-3 x-5 y = 63-56 y = 7(1)x + 14 = 21 x =在获得7的情况下,x = 7,y = 77。
假设5x + 7y = 525x + 2y = 22(1) - (2)5y = 30y = 6且(1)和5x + 42 = 525x = 10x = 2,则x = 2且y = 68。
5 x + 5 y = 65 x + y = 137 x + 7 y = 203 x + y = 29没有解9
8x + 4y = 56x + 4y = 21(1) - (2)给出7x = 35x = 5,并且如果(2)是5 + 4y = 214y = 16y = 4,则x = 5且y = 410。
5x + 7y = 415x + 8y = 44(2) - (1)如果y = 3输入到(1),则5x + 21 = 415x = 20x = 4,因此x = 4且y = 311。
7x + 5y = 543x + 4y = 384(1)-5(2)28x + 20y-15x-20y = 216-19013x = 26x = 2(2)6 + 4y = 384y = 32y = 8,所以= 2,y = 812。
x + 8y = 154x + y = 29(1)-8(2)x + 8y-32x-8y = 15-29 x 8-31x = -217x = 7(2)28 + y = 29y = 1然后它变为x = 7,y = 113。
3X + 6Y = 249x + 5Y = 463(1) - (2)得到:9X + 18Y-9X-5Y = 72-4613y = 26Y = 2(2)得到9X + 10 = 469X = 36X = 4,从而= 4,y = 214。
9x + 2y = 624x + 3y = 363(1)-2(2)27x + 6y-8x-6y = 186-7219x = 114x = 6(2)24 + 3y = 363y = 12y = 4 6,y = 415。
9x + 4y = 467x + 4y = 42(1) - (2)2x = 4x = 2和(1)18 + 4y = 464y = 28y = 7且x = 2,y = 716。
9x + 7y = 1354x + y = 417(2) - (1)28x + 7y-9x-7y = 287-13519x = 152x = 8(2)32 + y = 41y = 9因此x = 8它变成了。y = 9