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# Simultaneous equation help please watch

1. Solve the simultaneous equation y+x=7 and y=x^2+3x-5
X= or x=
Y= or y=
So far I've got:
X=7-y
Y=49-14y+y^2+21-3y-5
Y=y^2+17y+65
2. (Original post by Musicanor)
Solve the simultaneous equation y+x=7 and y=x^2+3x-5
X= or x=
Y= or y=
So far I've got:
X=7-y
Y=49-14y+y^2+21-3y-5
Y=y^2+17y+65
Why are you doing it in terms of Y when the second equation is in terms of X.
Try again but cancel the Ys and solve for X
3. (Original post by Musicanor)
Solve the simultaneous equation y+x=7 and y=x^2+3x-5
X= or x=
Y= or y=
So far I've got:
X=7-y
Y=49-14y+y^2+21-3y-5
Y=y^2+17y+65
If you go through this route then re-check your last line and take the y over to the same side as .

As 'jay' said, it is easier to substitute y instead.
4. (Original post by simon0)
If you go through this route then re-check your last line and take the y over to the same side as .

As 'jay' said, it is easier to substitute y instead.

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