Answer: B. -4
When 2 equations equal the same thing (in this case y) we can just re-write the equations this way:
3x + 1 = 2x - 3
Now, just start picking off little numbers that we don’t really need to get the x alone. I don’t like working with negative numbers, so i’ll get rid of the -3 by adding 3 to it. Since anything you do on one side of an equal sign you have to do on the other, i’ll add 3 to 1, which looks like this:
3x + 1 = 2x - 3
+3 +3
3x + 4 = 2x
Now I need to get both x’s on the same side, so i’ll subtract 3x from 3x, then subtract 3x from 2x:
3x + 4 = 2x
-3x -3x
4= -x
Variables should never be negative, and they look complicated too, so in order to make x positive again i’ll swap it’s side with 4. While doing this, remember that swapping sides means you swap 4 to a negative too:
4 = -x
x= -4
And there’s the answer, X equals -4. If you wanted to solve for y, just plug in the x value (which is -4 in this case) to any one of the equations:
y= 3x + 1
y= 3(4) + 1
y= 12+ 1
y= 13
Hope this helped!
