Draw the graph of equation 3x - 4y = 12. Use the graph drawn to find :

(i) y₁, the value of y, when x = 4

(ii) y₂, the value of y, when x = 0.

Step 1:

Give at least three suitable values to the variable x and find the corresponding values of y.

Let x = -2, then 3 $\times$ (-2) - 4y = 12 ⇒ y = -4.5

Let x = 1, then 3 $\times$ 1 - 4y = 12 ⇒ y = -2.2

Let x = 2, then 3 $\times$ 2 - 4y = 12 ⇒ y = -1.5

Let x = 4, then 3 $\times$ 4 - 4y = 12 ⇒ y = 0

Step 2:

Make a table (as given below) for the different pairs of the values of x and y:

Step 3:

Plot the points, from the table, on a graph paper and then draw a straight line passing through the points plotted on the graph.

(i) To find y₁, the value of y, when x = 4:

Through the point x = 4, draw a horizontal line which meets the y-axis at y = 0.

Hence, the value of y, when x = 4 is 0 , i.e, y₁ = 0.

(ii) To find y₂, the value of y, when x = 0:

Through the point x = 0, draw a vertical line which meets the y-axis at x = -3.

Hence, the value of y, when x = 0 is -3 , i.e, y₂ = -3.