Step-by-step explanation:
the answer is

..................
if it feels wrong
be free to correct ....
It will be -5 I pretty sure but I’m not sure
Are you supposed to assume that the function y is linear or that it is quadratic?
576-400
If linear, find the slope: m = ------------- = 176
6-5
Then the equation you want is y-400 = 176(x-5), or
y = 176x - 880 + 400, or y = 176 - 480.