Final answer:
Yes, the equation x+y=4 defines y as a function of x. When we rearrange the equation by solving for y, we find that y is expressed in terms of x.
Step-by-step explanation:
Yes, the equation x+y=4 defines y as a function of x. A function is a relationship between two variables where each value of the independent variable (x) corresponds to exactly one value of the dependent variable (y). In this equation, for every value of x, we can find a unique value of y that satisfies the equation.
To determine whether an equation represents a function, we can rearrange the equation to solve for y. In this case, we subtract x from both sides of the equation: y = 4 - x. The variable y is expressed in terms of x, indicating that y is indeed a function of x.