1. Solve Equations 2x+5y=21,x+2y=8 using Gauss Elimination Back Substitution method
Solution:
Total Equations are `2`
`2x+5y=21 -> (1)`
`x+2y=8 -> (2)`
Converting given equations into matrix form
`R_2 larr R_2-1/2xx R_1`
= | | `2` | `5` | | `21` | | | `0` `0=1-1/2xx2` `R_2 larr R_2-1/2xx R_1` | `-1/2` `-1/2=2-1/2xx5` `R_2 larr R_2-1/2xx R_1` | | `-5/2` `-5/2=8-1/2xx21` `R_2 larr R_2-1/2xx R_1` | |
|
`i.e.`
`2x+5y=21 ->(1)`
`-1/2y=-5/2 ->(2)`
Now use back substitution method
From (2)
`-1/2y=-5/2`
`=>y=-5/2xx-2=5`
From (1)
`2x+5y=21`
`=>2x+5(5)=21`
`=>2x+25=21`
`=>2x=21-25=-4`
`=>x=(-4)/(2)=-2`
Solution using back substitution method.
`x = -2`
`y = 5`
This material is intended as a summary. Use your textbook for detail explanation.
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