In this equation, you are solving for y. Simply isolate the variable by adding 1/4 to each side. The -1/4 and 1/4 will cancel out on the right side of the equation, leaving only y:
Slope intercept form is . The -intercept is -1 so we have . To find , look at the points and . The line goes up 1 and over 4, so the slope, , equals . Thus the full equation is