Answer:
4x and -3x
Explanation:
We can simplify only like terms in an algebraic expression.
Terms are "like terms" only if they consist the same letters with the same exponent.
The only difference between like terms is their coefficients are different.
So:
2y and 2y² are not like terms (different exponents at y)
4x and -3x are like terms (the same letter, the same exponent)
-3x and 32 aren't like terms (no x with 32 means different exponents)
or if you meant:
-3x and 3z aren't like terms (different letters)
3z and 4z² aren't like terms (different exponents at z)