Need help I’m in a test and I don’t understand

F(x) = x2 − 9, and g(x) = x − 3 f(x) = x2 − 4x + 3, and g(x) = x − 3 f(x) = x2 + 4x − 5, and g(x) = x − 1 f(x) = x2 − 16, and g(x) = x − 4 h(x) = x + 5 arrowright h(x) = x + 3 arrowright h(x) = x + 4 arrowright h(x) = x − 1 arrowright

What is the equation of this graphed line? enter your answer in slope-intercept form in the box.

Why is studying fractions important