Question

Find the slope of the line with equation 4x - 5y = 20. (Hint: Finding some points on the line first - perhaps the x- and y-intercepts - may help you find the slope.)

Answer 1

The slope formula is :

`m=(y_2-y_1)/(x_2-x_1)`

From the problem, we have the equation :

`4x-5y=20`

Find two points on the line (x and y intercepts)

For x intercept, let y = 0

`\begin{gathered} 4x-5(0)=20 \\ 4x=20 \\ x=(20)/(4)=5 \end{gathered}`

For y intercept, let x = 0

`\begin{gathered} 4(0)-5y=20 \\ -5y=20 \\ y=(20)/(-5)=-4 \end{gathered}`

The points are (5, 0) and (0, -4)

Using the formula above :

`\begin{gathered} m=(-4-0)/(0-5)=(-4)/(-5) \\ m=(4)/(5) \end{gathered}`

ANSWER :

The slope is 4/5