The task of Mathematical Statistics 2

The task of Mathematical Statistics 2

Problem number 2.
Given correlation table.
10 15 20 25 30 35 40
30 January 4
40 June 4
50 2 50 2
60 1 July 9
70 4 3 7
80 March 5

Using the raw data, get a sample equation of the form y ̅_x-y ̅ = r_b σ_y / σ_x (xx ̅) regression line Y on X.