Answer: 4x - 3y (choice B)
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Explanation:
The letter x is a variable, and a placeholder for a number. Which number? We don't know. It's basically a box where a number goes inside.
x represents having 1 box
2x is two boxes, and so on
If we add 3x and 1x, then we'll have four boxes and 3x+1x = 4x
We can only add the x terms together, which we consider to be called "like terms".
The y terms -5y and 2y are the other pair of like terms, which combine to -3y
If you want, you can draw a vertical number line. Start at -5 which is five units below zero. Then move up two spaces to arrive at -3. This is a visual way to demonstrate that -5+2 = -3, and by extension, -5y+2y = -3y
