Friday, May 31, 2013

`3x - y = 9, x - 2y = -2` Solve the system of linear equations and check any solutions algebraically.

`3x-y=9`


`x-2y=-2`


From the second equation,


`x=-2+2y`


Substitute the above expression of x in the first equation,


`3(-2+2y)-y=9`


`-6+6y-y=9`


`-6+5y=9`


`5y=9+6`


`5y=15`


`y=15/5`


`y=3`


Plug the value of y in the expression,


`x=-2+2y`


`x=-2+2*3`


`x=-2+6`


`x=4`


Now let's check the solution by plugging in the equations,


Plug in the solutions in the first equation,


`3*4-3=9`


9=9


Plug in the solution in the second equation,


`4-2*3=-2`


`4-6=-2`


`-2=-2`


Solutions satisfy both the equations


Hence the solutions of the equations are x=4 and y=3

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