solve simultaniously for x and y
Solve the following pairs of simultaneous equations for x and y:
(a + b)x + cy = bc
(b + c)y + ax = -ab
unsure how to start any help would be greatful!
Also write s in terms of a in the following pairs of equations
1) s = ah
h = 2a + 1
2) s = h^2 + ah
h = 3a^2
...(1)
...(2)
Working on (1) to make x the subject
Now sub this into (2) for x
exapnding in the a and separately dividing the denominators
Grouping the y terms together
Taking out y as a common factor
and finally dividing
You can simplify further and sub back in to find x.
I'd be inclined to use the elimination method:
Multiply equation (1) by a and equation (2) by (a + b), then substract one equation from the other and make y the subject.
Then, multiply equation (1) by (b + c) and equation (2) by c, then substract one equation from the other and make x the subject.