Well I think it's 10 hours and 20 minutes you just have to count the hours but subtract one hour because of lunch then add the remaining minutes.
Equation of a line in standard form is Ax + By = C
A is a pos. integer and B + C are integers
1) multiply all terms in the equation by 2
2y = x - 6
2) subtract 2y from both sides
2y - 2y (cancelled out) = x - 2y - 6
x - 2y - 6 = 0
3) add 6 to both sides
x-2y = 0 +6 (-6 and +6 cancel out)
therefore,
x - 2y = 6
is the equation in standard form