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Solve the linear system of equations using substitution: `-x+2/9y=1` ...
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High School Teacher
To solve using substitution, first rearrange one of the equations to reflect either x=...or y=...
`9x+3y=6` becomes `9x=6-3y`
`therefore x=6/9-3/9 y`
Now substitute the x value into the first equation. it is not necessary to simplify the `6/9` as it will be easier to use like that later:
`-(6/9 - 3/9 y) +2/9y = 1`
`therefore -6/9 + 3/9 y +2/9 y = 1` (note the symbols (-) changes)
`therefore 3/9 y + 2/9 y = 1 + 6/9`
`therefore 5/9 y = 9/9 +6/9`
`therefore 5/9 y = 15/9`
`therefore y=15/9 times 9/5`
Now substitute into any previous equation to solve for x:
`9x +3y = 6` becomes `9x + 3(3) = 6`
`therefore x= -1/3`
Ans: (x;y) : ( `-1/3` ; 3)
Posted by durbanville on July 30, 2013 at 4:43 AM (Answer #1)
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