Question

Draw the graph of xy = 20, x , y> 0. Use the graph to find y when x = 5 and to

find x when y = 10.​

Answer 1

To draw:

Graph of xy = 20 , when x > 0 and y > 0.

Then find the value of :

• y when x = 5

• x when y = 10

Solution:

The given equation is:

$\boxed{ \bold{x \: y = 20}}$

$= > \bold{ y = \dfrac{20}{x} \: \: \: \: ......(eq.)}$

• The graph of this equation will be a hyperbola.

• Refer to the attached diagram to see the hyperbolic curve.

When x = 5 :

$= > \bold{ y = \dfrac{20}{x} }$

$= > \bold{ y = \dfrac{20}{5} }$

$\boxed{ = > \bold{ y = 4}}$

When y = 10 :

$= > \bold{ y = \dfrac{20}{x} }$

$= > \bold{ x= \dfrac{20}{y} }$

$= > \bold{ x= \dfrac{20}{10} }$

$\boxed{ = > \bold{ x= 2}}$

• Refer to the 2nd image to see the required points plotted on the curve.

Hope It Helps.