Question

3x-7y=21
Plot the graph of this equation.
Find the points showing calculations where the line cuts x-axis and y-axis. Also mark these ponits on graph.
Check if the point 4,2 lies on the line​

Answer 1

$\large\underline{\sf{Solution-}}$

Given equation of line is

$\rm :\longmapsto\:3x - 7y = 21$

Substituting 'x = 0' in the given equation, we get

$\rm :\longmapsto\:3(0) - 7y = 21$

$\rm :\longmapsto\: - 7y = 21$

$\rm :\longmapsto\: y = - 3$

Substituting 'y = 0' in the given equation, we get

$\rm :\longmapsto\:3x - 7(0) = 21$

$\rm :\longmapsto\:3x - 0 = 21$

$\rm :\longmapsto\:3x = 21$

$\rm :\longmapsto\:x =7$

Hᴇɴᴄᴇ,

➢ Pair of points of the given equation are shown in the below table.

$\begin{gathered}\boxed{\begin{array}{c|c} \bf x & \bf y \\ \frac{\qquad \qquad}{} & \frac{\qquad \qquad}{} \\ \sf 0 & \sf - 3 \\ \\ \sf 7 & \sf 0 \end{array}} \\ \end{gathered}$

➢ Now draw a graph using the points (0 , - 3) & (7 , 0)

➢ See the attachment graph.

From graph, we conclude that point ( 4, 2 ) donot lies on it.