If the system of linear equations
3x+y+βz=3
2x+αy−z=−3
x+2y+z=4
has infinitely many solution, then the value of 22β−9α is:
Explanation
3x+y+βz=3
2x+αy−z=−3
x+2y+z=4
D=321amp;1amp;αamp;2amp;βamp;−1amp;1
Dx=3−34amp;1amp;αamp;2amp;βamp;−1amp;1
Dy=321amp;3amp;−3amp;4amp;βamp;−1amp;1
Dz=321amp;1amp;αamp;2amp;3amp;−3amp;4
There are infinite many solution, therefore, D=0=Dx=Dy=Dz
D=0=321amp;1amp;αamp;2amp;βamp;−1amp;1
⇒3α+4β−αβ+3=0
Dz=0=321amp;1amp;αamp;2amp;3amp;−3amp;4
⇒0=9α+19
α=9−19,β=116
⇒22β−9α=31
Explanation
3x+y+βz=3
2x+αy−z=−3
x+2y+z=4
D=321amp;1amp;αamp;2amp;βamp;−1amp;1
Dx=3−34amp;1amp;αamp;2amp;βamp;−1amp;1
Dy=321amp;3amp;−3amp;4amp;βamp;−1amp;1
Dz=321amp;1amp;αamp;2amp;3amp;−3amp;4
There are infinite many solution, therefore, D=0=Dx=Dy=Dz
D=0=321amp;1amp;αamp;2amp;βamp;−1amp;1
⇒3α+4β−αβ+3=0
Dz=0=321amp;1amp;αamp;2amp;3amp;−3amp;4
⇒0=9α+19
α=9−19,β=116
⇒22β−9α=31