What does the y-intercept mean in terms of the problem?

The vet charges $45 for an office visit and $10 for each vaccination your dog needs. write an eaquation

If you double the input of a function and it results in half the output, and if you triple the input and it results in a third of the output, what can be guessed about the function? check all that apply.

Which best explains why this triangle is or is not a right triangle ?