Year 12s: what will be the first way you research your future options? >>

Simultaneous equations

2662857

I can do the first bit but always get confused with the second

Reply 1

HapaxOromenon3

Original post by Jack_Tomlin

I can do the first bit but always get confused with the second

You now have a -6y and a +6y which will cancel, so add the equations to give 18x+8x = 99+18 -> 26x=117 -> x=4.5.
Now substitute this into any of the equations to give y = -3.

Reply 2

2662857

What have I messed up?

Original post by HapaxOromenon3

You now have a -6y and a +6y which will cancel, so add the equations to give 18x+8x = 99+18 -> 26x=117 -> x=4.5.
Now substitute this into any of the equations to give y = -3.