Answer:
(3rd option)
Explanation:
Long and tedious way: it goes through the points (1;1) and (-1;-3). it's a system of equation in m and q. It works, it tells us nothing about what the two things are.
More interesting: the slope of a line measures how much y varies when x varies by 1 unit. It's easy to spot that for an increase of 1 anywhere in the graph - but we're going to pick a convenient spot, ie from 0 to 1 - we have an increase in y from -1 to 1: 2 units. Our slope is then 2. The intercept tells us where the line crosses the y axis, ie at -1. We can then build our equation:
