#1**+1 **

Here's the key

Simplify both sides

If one side = the other side, we have infinite solutions

(Hint : look at the first one)

CPhill Feb 5, 2021

#2**0 **

An equation can have infinite solutions if the variables go away and you are left with something like "5 = 5" or "7 = 7".

Guest Feb 5, 2021

#3**0 **

I believe that the first equation leaves you with -7 = -7 for any number "n". (This has infinite solutions)

The second equation leaves: -15 = 10. No value of "n" works for this. (This has no solutions)

The third equation leaves: -3 = 10. (This also has no solutions)

The last equation leaves you with n = 2. (This is only one solution.)

Guest Feb 5, 2021