Okay, first thing is you want to have x and y all alone. So you need to solve the equations.
Equation 1:
5x+4y=12 (you want to subtract 5x on both sides to get y on one side and x on the other)
5x+4y=12
-5x -5x
4y=12-5x (Now if you want x and y alone you want to divide 4 on both sides)
4
y=3-1.25x Now that's you equation
Equation 2: (Basically the same steps for the 1st equation)
3x-3y=18 (Subtract 3x on both sides)
-3x -3x
-3y=18-3x (Now you divided by -3 on both sides)
-3
y=-6+x (you might notice why is there only 1 x, well because -3 divided by -3 is going to be a positive 1. You can either put a "x" or a 1x, doesn't really matter).
now since you have the two equations simplified you want to solve by doing multi-step.
3-1.25x=-6+x (Now you want to add 1.25x so you can get rid of the negative x)
+1.25x +1.25x
3= -6+2.25 (Remember x alone is like 1, so it's like 1+1.25, next you want to add 6 on both sides. So you have a number and a variable all alone).
3=-6+2.25x
+6 +6
9 = 2.25x (Next you divided 2.25 on both sides)
2.25 2.25
Answer:
x =4
If your not sure, you can plug in or replace x with 4. :D
I really do hope this help you understand :D
