SOLUTION: hey my name is jhon and i want to know how to solve solving sysytem sbstution

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Question 28354:
hey my name is jhon and i want to know how to solve solving sysytem sbstution

Answer by elima(1433) About Me  (Show Source):
You can put this solution on YOUR website!
You mean solving equations by substitution?
ex;
2x-9y=1
x-4y=1
You would first solve one of the equations for one of the variables;
x-4y=1
x=1+4y
Now you substitute that in the other equation for x;
2(1+4y)-9y=1
2+8y-9y=1
2-y=1
-y=1
y=-1
Now plug that into the equation for y and find x;
2x-9(-1)=1
2x+9=1
2x=1-9
2x=-8
x=-4
Now you have x & y ;
x=-4; y=-1
hope this is what you were having problems on, and it helps. If not let me know
=)