### Instruction: Simplify the following expression in $x$:

$$3x + 2 - 5x + 18$$.### Response: I notice that there are two terms with $x$ and two terms that are constants.
I can combine the like terms by adding or subtracting them.
For the terms with $x$, I have $3x - 5x = -2x$.
For the constants, I have $2 + 18 = 20$.
So the simplified expression is $-2x + 20$.