Question

What is the standard form equation of the line passing through (1, –5) with a slope of –1?

x – y = –4

x – y = 4

x + y = –4

x + y = 4

Answer 1

well you dont need to know the info about slope here in this case..you can use hit an trial
note that only of the options satisfy (1,-5)

Answer 2

i still don't understand .

Answer 3

can you find the value of x+y for (1,2) ?