Question
Draw the graph of linear equation 4x + 3y = 36. From the graph, find the value of y when x = 3 and value of x when y = 6.
Solution
4x + 3y = 36 ....(1)
3y = 36 - 4x
Table of solutions
|
X |
0 |
9 |
|
y |
12 |
0 |
We plot the points (0, 12) and (9,0) on a graph paper and join the same by a ruler to get the line which is the graph of the equation (1).
Mark a point P(3, 0) on x-axis. From P draw PQ || y-axis to intersect the graph at Q. From Q, draw QR || x-axis to intersect the y-axis at R(0, 8).
Hence, y = 8 when x = 3.
Again, mark a point A(0, 6) on y-axis. From A draw AB II x-axis to intersect the graph at B. From B, draw BC || y-axis to intersect x-axis at 
.
Hence 
when y = 6
