# Math

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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.

• Math -

to get rid of the y's we make this a simultaneous equation
(1)4x-y=-9
(2)3Y-2X=7
the number of y's must be equal so that they will cancel eachother out when we add them together
so 3*(1)=12x-3y=-27
then we do (1)+(2)
12x-3y+3y-2x=-27+7
hopefully you will see that the y's cancel eachother out and we are left with
10x=-20
therefor x=-2

if you are unsure with any of the steps feel free to ask :)

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