Need help asap

4

Step-by-step explanation:

x-x = 0

then:

y + x - x = y + 0 = 0

if y = 4

y + x - x = 4

they are simplified

step-by-step explanation:

this linear equation would have just one solution.

step-by-step explanation:

the reason why this would have one solution is that it is an expression with just one variable. since that variable is not raised to a power, it will always have just one solution.