The equation of a line in intercept-slope form is given by the following expression:
y = mx + b
Where m is the slope and b is the y-intercept.
We can find the slope of the line by means of the following formula:
Where (x1, y1) and (x2, y2) are two points where the line passes through.
In this case, we have some points in a table, then let's use two of them, for example, take (-2, 15) and (2, -5). By replacing (-2, 15) for (x1, y1) and (2, -5) for (x2, y2) we get:
Now that we know the value of the slope, we can replace 5 for m into the slope-intercept form to get:
y = 5x + b
By taking another pair of x and y-values from the table and, for example (6, -25), and replacing -25 for y and 6 for x, we get:
-25 = 5×6 + b
-25 = 30 + b
-25 - 30 = 30 - 30 + b
-55 = b
b= -55
Now that we know the value of the y-intercept, we can replace -55 for b into the slope-intercept equation of the line, to get:
y = 5x - 55
Then, the equation of the line that describes the given data is y = 5x - 55