Write a linear function f with f(0)=7 and f(3)=1

Question

I am having trouble with figuring out how to get the equation, i don't understand. If you could somehow explain, then that would be nice.

Answer 1

Start with

y = mx + b

Now use the 2 given points to find m and b.

7 = m(0) + b

b = 7

1 = m(3) + 7

m = -2

f(x) = -2x + 7

Test the answer.