The equation, in slope-intercept form, of each of the following graphs of linear relations are:
1. y = 1/2(x) - 1.
2. y = -3x
3. y = 16x + 400
In Mathematics and Euclidean Geometry, the intercept form of the equation of a standard line can be modeled by the following formula;
x/a + y/b = 1
Where:
a and b are x-intercept and y-intercept respectively.
Part 1
Since the graph of the straight line function has an x-intercept at (2, 0) and a y-intercept at (0, -1), an equation that represents the line can be written as follows;
x/2 - y/1 = 1
(x - 2y)/2 = 1
x - 2y = 2
y = x/2 - 2/2
y = 1/2(x) - 1
Part 2
Since the graph pass through the origin (0, 0), it represents a proportional relationship;
y = mx
y = (3/-1)x
y = -3x
Part 3.
At data point (0, 400) and a slope of 16, an equation for this line can be calculated by using the point-slope form as follows:

y - 400 = 16(x - 0)
y = 16x + 400