线性代数 示例
x+2y-z=4x+2y−z=4 , 2x+y+z=-22x+y+z=−2 , x+2y+z=2x+2y+z=2
解题步骤 1
Write the system as a matrix.
[12-14211-21212]⎡⎢
⎢⎣12−14211−21212⎤⎥
⎥⎦
解题步骤 2
解题步骤 2.1
Perform the row operation R2=R2-2R1R2=R2−2R1 to make the entry at 2,12,1 a 00.
解题步骤 2.1.1
Perform the row operation R2=R2-2R1R2=R2−2R1 to make the entry at 2,12,1 a 00.
[12-142-2⋅11-2⋅21-2⋅-1-2-2⋅41212]⎡⎢
⎢⎣12−142−2⋅11−2⋅21−2⋅−1−2−2⋅41212⎤⎥
⎥⎦
解题步骤 2.1.2
化简 R2R2。
[12-140-33-101212]⎡⎢
⎢⎣12−140−33−101212⎤⎥
⎥⎦
[12-140-33-101212]⎡⎢
⎢⎣12−140−33−101212⎤⎥
⎥⎦
解题步骤 2.2
Perform the row operation R3=R3-R1R3=R3−R1 to make the entry at 3,13,1 a 00.
解题步骤 2.2.1
Perform the row operation R3=R3-R1R3=R3−R1 to make the entry at 3,13,1 a 00.
[12-140-33-101-12-21+12-4]⎡⎢
⎢⎣12−140−33−101−12−21+12−4⎤⎥
⎥⎦
解题步骤 2.2.2
化简 R3R3。
[12-140-33-10002-2]⎡⎢
⎢⎣12−140−33−10002−2⎤⎥
⎥⎦
[12-140-33-10002-2]⎡⎢
⎢⎣12−140−33−10002−2⎤⎥
⎥⎦
解题步骤 2.3
Multiply each element of R2R2 by -13−13 to make the entry at 2,22,2 a 11.
解题步骤 2.3.1
Multiply each element of R2R2 by -13−13 to make the entry at 2,22,2 a 11.
[12-14-13⋅0-13⋅-3-13⋅3-13⋅-10002-2]⎡⎢
⎢⎣12−14−13⋅0−13⋅−3−13⋅3−13⋅−10002−2⎤⎥
⎥⎦
解题步骤 2.3.2
化简 R2R2。
[12-1401-1103002-2]⎡⎢
⎢⎣12−1401−1103002−2⎤⎥
⎥⎦
[12-1401-1103002-2]⎡⎢
⎢⎣12−1401−1103002−2⎤⎥
⎥⎦
解题步骤 2.4
Multiply each element of R3R3 by 1212 to make the entry at 3,33,3 a 11.
解题步骤 2.4.1
Multiply each element of R3R3 by 1212 to make the entry at 3,33,3 a 11.
[12-1401-1103020222-22]⎡⎢
⎢
⎢⎣12−1401−1103020222−22⎤⎥
⎥
⎥⎦
解题步骤 2.4.2
化简 R3R3。
[12-1401-1103001-1]⎡⎢
⎢⎣12−1401−1103001−1⎤⎥
⎥⎦
[12-1401-1103001-1]⎡⎢
⎢⎣12−1401−1103001−1⎤⎥
⎥⎦
解题步骤 2.5
Perform the row operation R2=R2+R3R2=R2+R3 to make the entry at 2,32,3 a 00.
解题步骤 2.5.1
Perform the row operation R2=R2+R3R2=R2+R3 to make the entry at 2,32,3 a 00.
[12-140+01+0-1+1⋅1103-1001-1]⎡⎢
⎢⎣12−140+01+0−1+1⋅1103−1001−1⎤⎥
⎥⎦
解题步骤 2.5.2
化简 R2R2。
[12-1401073001-1]⎡⎢
⎢⎣12−1401073001−1⎤⎥
⎥⎦
[12-1401073001-1]⎡⎢
⎢⎣12−1401073001−1⎤⎥
⎥⎦
解题步骤 2.6
Perform the row operation R1=R1+R3R1=R1+R3 to make the entry at 1,31,3 a 00.
解题步骤 2.6.1
Perform the row operation R1=R1+R3R1=R1+R3 to make the entry at 1,31,3 a 00.
[1+02+0-1+1⋅14-101073001-1]⎡⎢
⎢⎣1+02+0−1+1⋅14−101073001−1⎤⎥
⎥⎦
解题步骤 2.6.2
化简 R1R1。
[120301073001-1]⎡⎢
⎢⎣120301073001−1⎤⎥
⎥⎦
[120301073001-1]⎡⎢
⎢⎣120301073001−1⎤⎥
⎥⎦
解题步骤 2.7
Perform the row operation R1=R1-2R2R1=R1−2R2 to make the entry at 1,21,2 a 00.
解题步骤 2.7.1
Perform the row operation R1=R1-2R2R1=R1−2R2 to make the entry at 1,21,2 a 00.
[1-2⋅02-2⋅10-2⋅03-2(73)01073001-1]⎡⎢
⎢
⎢
⎢⎣1−2⋅02−2⋅10−2⋅03−2(73)01073001−1⎤⎥
⎥
⎥
⎥⎦
解题步骤 2.7.2
化简 R1R1。
[100-5301073001-1]⎡⎢
⎢
⎢⎣100−5301073001−1⎤⎥
⎥
⎥⎦
[100-5301073001-1]⎡⎢
⎢
⎢⎣100−5301073001−1⎤⎥
⎥
⎥⎦
[100-5301073001-1]⎡⎢
⎢
⎢⎣100−5301073001−1⎤⎥
⎥
⎥⎦
解题步骤 3
Use the result matrix to declare the final solution to the system of equations.
x=-53x=−53
y=73y=73
z=-1z=−1
解题步骤 4
The solution is the set of ordered pairs that make the system true.
(-53,73,-1)(−53,73,−1)