Скачать или смотреть Class 9 Maths Chapter 4 Linear equations in two variables Exercise 4.3 Questions 7 and 8

Let distance travelled by body and work done by body be d and w respectively.
Work done  distance traveled
w  d
w = kd   
Where k is a constant
If constant force is 5 units, work done w = 5d   
Now we may observe that point (1, 5) and (-1, -5) satisfy the above equation.
So (1, 5) and (-1, -5) are solutions of this equation.
The graph can be drawn as follows:

                        

 

(i)     From the graphs we may observe that the value of y corresponding to x = 2 is 10. Thus the work done by the body is 10 units when the distance traveled by it is 2 units.  

(ii)    From the graphs we may observe that the value of y corresponding to x = 0 is 0. Thus the work done by the body is 0 units when the distance traveled by it is 0 unit.   

Solution 7

Let Yamini and Fatima contributed x and y repectively towards the Prime Minister's Relief fund.
Amount contributed by Yamini + amount contributed by Fatima = 100
x + y = 100  
Now we observe that (100, 0) and (0, 100) satisfy the above equation.
So, (100, 0) and (0, 100) are solutions of above equation.
The graph of equation x + y = 100 can be drawn as follows:  

 

                               

 

Here we may find that variable x and y are representing the amount contributed by Yamini and Fatima respectively and these quantities may not be negative. Hence we will consider only those values of x and y which are lying in 1st quadrant.

Solution 8

(i)   

 

We may observe that point (0, 32) and (-40, -40) satisfy the given equation. So these points are solutions of this equation.
Now we can draw the graph of above equation as below

 

                                   

 

(ii)    Temperature = 30oC                                         

        

 

        So temperature is Fahrenheit is 86o F.      

(iii)    Temperature = 95o F    

 

          

 

 

      So temperature in Celsius is 35oC.

 

(iv)

       

      So, if C = 0oC, F = 32o F     
      If F = 0o

      

So if F = 0oF, C = - 17.8oC

 

(v)  

         

Yes there is a temperature - 40o which is numerically same in both Fahrenheit and Celsius. 




link of exercise 4.3



   • Class 9 Maths Chapter 4 Linear equations i...  


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