Are the expressions x + x + x + x and 4x equivalent?

Yes

Step-by-step explanation:

x+x+x+x is added four times, which is equivalent to multiplying 4 times x, or 4x.

If we were to substitute any number in for x, we would get the same number from both expressions

Let's say x=4

x+x+x+x

4+4+4+4

16

4x

4*4

16

yup

Step-by-step explanation:

when there's a variable without a number in front of it it means that it equals 1. x+x+x+x=4x