Let present age of Manish be x years and present age of Rahim be y years.
Case I. x = 3y
⇒ x - 3y = 0
Case II.
After 5 years :
Age of Manish = (x + 5) years
Age of Rahim = {y + 5) year
Fig. 3.18.
According to question
x + 5 = 2(y + 5)
⇒ x + 5 = 2y + 10
⇒ x - 2y = 10 - 5
⇒ x - 2y = 5
So, algebraic representation be
x - 3y = 0 ...(i)
x - 2y = 5 ...(ii)
Graphical representation
For eqn. (i), we have
x - 3y = 0
⇒ x = 3y
Thus, we have following table :
For eqn. (ii), we have
x - 2y = 5
⇒ x = 5 + 2y
Thus, we have following tables :
When we plot the graph of the equation, we find that both the lines intersect at one point.
Hence, given system of equations has a unique solution.
So, we can say that system is consistent.
Represent the following system of linear equations graphically from the graph find the points where the lines intersect y-axis.
3x + y - 5 = 0, 2x - y - 5 = 0
Draw the graphs of the equations :
x - y = 1
and 2x + y = 8
Determine the vertices of the triangle formed by these lines and x-axis.