A line is shown on the coordinate plane.

On coordinate plane, points (2, 1), (1, 5) and (0, 9) are connected through a line.

Drag a number to each box to represent the equation of the line.

To find the equation of a line, we can use the slope-intercept form, which is y = mx + b, where m is the slope and b is the y-intercept.

To find the slope, we can use the formula m = (y2 - y1) / (x2 - x1), where (x1, y1) and (x2, y2) are two points on the line.

Using the given points (2, 1) and (1, 5):

m = (5 - 1) / (1 - 2) = 4 / -1 = -4

Now that we have the slope, we can plug it into the slope-intercept form along with one of the points to find the y-intercept.

Using the point (0, 9):

9 = -4(0) + b
9 = b

So the equation of the line is y = -4x + 9.