Rewrite the equation in the slope-intercept form.
3x + y = 3
Subtracting -3x from both sides we get this:
y = -3x + 3
This is just a straight line.
Here, x can be any real number.
When x is any real number, the value of y is also any real number.
A straight line goes on forever in two directions. It really does not matter what number we select for x to find y.
Answer:
Domain is ALL REAL NUMBERS.
Range is ALL REAL NUMBERS.
Your math book may write the answer in interval notation:
Domain is (-00, 00); Range is (-00, 00).
Note:
-00 means negative infinity.
00 means positive infinity.
Still in some math books, the author(s) may decide to use set notation to express ALL REAL NUMBERS for the domain and range.
If so, we can also write the answer this way:
Domain = x = ALL R, where big R stands for real numbers.
Range = y = ALL R, where big R stands for real numbers.