Which one of the following is not explain why 2x+3y does not equal 5xy a. If You substitute 4 for x and 5 for y in the expression 2x+3y, it does not equal 5(4)(5). B. Since 2 and 3 are factors, they should be multiplied to get 6xy. C. X and y are not like terms. D. Adding x and y is not the same as multiplying x and y.