PLS HELP ik its rlly easy but I dont get it

You can find the constant of proportionality by finding the ratio of

The approximate line of best fit for the given data points, y = −2x − 2, is shown on the graph.which is the residual value when x = –2? a)–2 b)–1 c)1 d)2

Similarly fie each expression 18,19,20