A function is a relation between a set of inputs (called the domain) and a set of outputs (called the range) where each input is associated with exactly one output.
Out of the given options, the function is:
y = 2x + 1
In this equation, for every value of x, there is a unique corresponding value of y. Therefore, it satisfies the definition of a function.
The other options:
- y = |x| + 3: This equation represents the absolute value of x, which means that for negative values of x, the output will be the positive counterpart. Thus, it does not satisfy the definition of a function as it does not have a unique output for every input.
- y = x^2 + 3x: This equation represents a quadratic function. It does satisfy the definition of a function, as each input has a unique output.
- y = x^2 - 5x: This equation also represents a quadratic function and satisfies the definition of a function.
