Solve the following system:

y = x + 3
2x + y = 9

(2, 5)
(5, 2)
(−2, 5)
(2, −5)

Hi,

y = x+3
2x+y = 9

2x+(x+3) = 9
2x+x+3 = 9
3x+3 = 9
3x = 9-3
3x = 6
x = 6/3
x = 2

y = x+3
y = 2+3
y = 5

(x,y) = (2,5)

Ahhh easy:) all we have to do is plug in y
sooo this question becomes 
2x + x + 3 = 9 
we add the xs and they become 3x
s
3x + 3 = 9 
now subtract 3 from both sides
3x +3 = 9 
     - 3 = -3 
they cancel out on the left hand side and the right side of the equal sign becomes a 6 
s
3x = 6 
divide both sides by 3 
3x = 6 
÷3 = ÷ 3
the 3s on the left side cancel out
and the right side becomes 2
s
x = 2 
but before we can answer this completely we plug it into our first equation
s
y = x + 3 
to this 
y = 2 + 3 
so y = 5
x = 2 
y = 5 
coordinates?
(2, 5)