Note: Your equation expression seems a little unclear. So, I am assuming that your expression is
y = x - 4
The solution steps would anyway still clear your concept so that no matter what you can solve whatever the expression it is because the procedure remains the same.
Answer:
The value of y = -7 if x = -3
Explanation:
Assuming the given the expression

Given that we have to find the value of y if x = -3.
so substituting x = -3 in the equation




Therefore, the value of y = -7 if x = -3
The graph of the equation y = x- 4 is also attached below.