Q1 of 186 Page 3

Solve the following pair of linear equations by substitution method:

3x – y = 3


9x — 3y = 9

Given equations are


3x – y = 3 …(i)


9x – 3y = 9 …(ii)


From eqn (i), y = 3x – 3 …(iii)


On substituting y = 3x – 3 in eqn (ii), we get


⇒ 9x – 3(3x – 3) = 9


⇒ 9x – 9x + 9 = 9


⇒ 9 = 9


This equality is true for all values of x, therefore given pair of equations have infinitely many solutions.


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