Q9 of 102 Page 41

Solve the following equations by graphical method- 2x + 3y=8; 4x – 3/2y = 1

For solving these equations by the graphical method, we need to form separate tables for each equation.

We have the equations,


2x + 3y = 8 …(i)


…(ii)


Take equation (i), we have


2x + 3y = 8


We can write it as,


3y = 8 – 2x



Now, assign values of x and compute y.


We can assign values of x = …, -3, -2, -1, 0, 1, 2, 3, 4,…


It is not necessary to put all values. But to form an accurate graph, it is necessary to put atleast three values.


Say, we put x = 0.


Then,




y = 2.67


We have, (0, 2.67).


Now, put x = 1.


Then,




y = 2


We have, (1, 2).


Now, put x = 2.


Then,




y = 1.33


We have, (2, 1.33).


Now, put x = 3.


Then,




y = 0.67


We have, (3, 0.67).


We can further find out y by putting values of x = …,-5,-4,-3,…,6,7,… but here we have just put four values.


Record it in a table,



Now, take equation (ii),



We can write it as,



…(iv)


Assign values for x and compute it y.


For equation (iv):


Say, we put x = 0.


Then,




y = -0.67


We have, (0, -0.67).


Now, put x = 1.


Then,




y = 2


We have, (1, 2).


Now, put x = 2.


Then,





y = 4.67


We have, (2, 4.67).


Now, put x = 3.


Then,





y = 7.33


We have, (3, 7.33).


Record it in a table.



Represent the two tables on a graph, we get



Notice the intersection point of these two lines, 2x + 3y = 8 and .


These two lines intersect each other at (1, 2) in the 1st quadrant.


(1, 2) is the solution of these equations.


Thus, solution is x = 1 and y = 2.


More from this chapter

All 102 →