Jill also got the expression 7x+1,and then wrote her answer as 1x+7.is her expression an equivalent expression? how do you know

No it is not because she has a different number I front of the variable and in order for it to be equivalent it must be the same thing!

Hey there!
No, they're definitely not the same thing. This is because in the first equation you are multiplying 7 by the value of whatever x is and adding one. In the other equation, you're then multiplying the value of x by one and adding 7. With he restriction being negatives, you'd get a smaller answer when you did the second equation as opposed to the first because in the first you're multiplying by 7.
Hope this helps!