x - 4y = 21

Here we will show you how to calculate and provide solutions to math problems related to x - 4y = 21.

We will start by calculating and showing you the solution for the x-intercept and y-intercept of x - 4y = 21.

Then, we will show you how to get the graph plot coordinates for x - 4y = 21 so we can illustrate it on a graph.

Finally, we will solve x - 4y = 21 for x and also for y, then calculate and show you the solution for the slope of x - 4y = 21.

Find x-intercept
The x-intercept is where the graph crosses the x-axis. To find the x-intercept, we set y₁=0 and then solve for x.

x - 4y = 21
x - 4(0) = 21
x₁ = 21 y₁ = 0

Find y-intercept
The y-intercept is where the graph crosses the y-axis. To find the y-intercept, we set x₂=0 and then solve for y.

x - 4y = 21
1(0) - 4y = 21
y₂ = -5.25 x₂ = 0

Get Graph Plot Coordinates
Getting two graph points will allow you to make a straight line on a graph. The plot coordinate format is (x₁,y₁) and (x₂,y₂).

Thus, we use the x-intercept and y-intercept results above to get the graph plots for x - 4y = 21 as follows:

(x₁,y₁) and (x₂,y₂)
(21,0) and (0,-5.25)

Solve for x
To solve for x, we solve the equation so the variable x is by itself on the left side:

x - 4y = 21
x = 4y + 21

Solve for y
To solve for y, we solve the equation so the variable y is by itself on the left side:

x - 4y = 21
y = 0.25x - 5.25

Find slope
The slope of the line (m) is the steepness of the line. It is the change in the y coordinate divided by the corresponding change in the x coordinate. Simply plug in the coordinates from above and solve for m to get the slope for x - 4y = 21

m = (y₂ - y₁)/(x₂ - x₁)
m = (-5.25 - 0)/(0 - 21)
m = 0.25

Ax - By = C Calculator
Now you know how to solve x - 4y = 21. Enter another math problem here: