Question 201998
most of what you have done looks ok, but just need to do a little more
start at
2x+5x=28 solve
7x=28
x=4

---------------------substitute 4 for x in the y=5x
y=5x
y=5(4)
y=20              (4,20)
--------------------------
2nd problem, starting where you stopped
3(23-3y)-2y=3
69-9y-2y=3
69-11y=3
-11y=-69+3
11y=69-3
11y=66
y=6
---------------------------
3x-2y=3
3x-2(6)=3
3x-12=3
3x=15
x=5          (5,6)
when you are working these make sure you keep track of all parts of the equations. Then just work through one step at a time.