Here is an answer from 2 years ago from
vinginge Level 19 / Ex Rocker with eclectic tastes
Answered 2 years ago

E(X) = 0.6X - 2.8

My mathematics is a bit old fashioned but this looks like a different way of presenting two sets of ordered pairs of a straight line linear equation.
When X = 5, y = 0.2
When X = 6, y = 0.8

The slope is (0.8 - 0.2)/(6 - 5) = 0.6
Using the standard equation y = mx + c then when y = 0.8 and x = 6
0.8 = 0.6 x 6 + c : 0.8 = 3.6 + c : c = 0.8 - 3.6 = - 2.8
Therefore the equation now becomes, y = 0.6x - 2.8

Hopefully, this links into your style of presentation and can be adapted as shown at the top. If not, bin it as a load of rubbish.......Good Luck