Question

Show graphically that the following system of equations is in-consistent (i.e. has no solution) :

3x – 4y – 1 = 0

`2x - 8/3 y + 5 = 0`

Answer 1

The given equations are

3x - 4y - 1 = 0 .....(i)

`2x - 8/3 y + 5 = 0`

6x - 8y + 15 = 0 ...(ii)

Putting x = 0 in equation (i) we get

` => 3 xx 0 - 4y = 1`

`=> y = -1/4`

`=> x = 0, y = -1/4`

Putting y = 0 in equation (i) we get

`=> 3x - 4xx0 = 1`

`=> x = 1/2`

`=> x = 1/3, y = 0`

Use the following table to draw the graph.

x	0	`1/3`
y	`-1/4`	0

The graph of (i) can be obtained by plotting the two points `A(0, -1/4), B(1/3, 0)`

6x - 8y = -15  ....(ii)

Putting x = 0 in equation (ii) we get

`=> 6 xx 0 - 8y = -15`

`=> y = 15/8`

`=> x = 0, y = 15/8`

Putting y = 0 in equation (ii) we get

`=> 6x - 8 xx 0 = -15`

`=> x = -15/6`

`=> x = -5/2, y = 0`

Use the following table to draw the graph.

x	0	`-5/2`
y	`15/8`	0

Draw the graph by plotting the two point `C(0, 15/8), D(-5/2, 0)` from table

Here, the two lines are parallel.

Hence the given system of equations is inconsistent.