posted by Linda on .
1.Sally age is 12 years plus half her age. How old is she?
2.Given that: 4x-y+9=0 and 3y-2x=7, solve for x.
I'll answer 2.
to get rid of the y's we make this a simultaneous equation
the number of y's must be equal so that they will cancel eachother out when we add them together
then we do (1)+(2)
hopefully you will see that the y's cancel eachother out and we are left with
if you are unsure with any of the steps feel free to ask :)