Key idea to think about when approaching these type of questions, is to think of the fomula. What is the Standard Intergers Formula look like?
Ax + By = C
You have to rearrange the original formula in order to make X and Y on the same side on the equation.
y = -0/5x + 0.8
Because the coefficient of the X, is negative (-0.5x), then when placing it on the otherside, will change it into a positive.
Thus,
y + 0.5x = 0.8 (the 0.8 remains the same, since we hadnt moved it).
Taking note of positions. Rearrange so it equals the formula: Ax + By = C
∴ 0.5x + y = 0.8
So there its in standardized form.
A = 0.5
B = 1
C = 0.8
I hope this helped.