Ex 3.3, 1
Solve the following pair of linear equations by the substitution method.
(iii) 3x – y = 3
9x – 3y = 9
3x – y = 3
9x – 3y = 9
Solving (1)
3x – y = 3
3x = y + 3
x = (𝒚 + 𝟑)/𝟑
Putting value of x in (2)
9x – 3y = 9
9((𝑦 + 3)/3)−3𝑦=9
3(y + 3) – 3y = 9
3y + 9 – 3y = 9
3y – 3y + 9 = 9
0 + 9 = 9
9 = 9
The statement is true for all values of x
So, there are infinitely many solutions
Reason :-
The 2 equations given in question are
3x – y = 3
9x – 3y = 9
From (2), taking 3 common , we get
3 (3x – y) = 9
3x – y = 9/3
3x – y = 3
Which is equation same as equation (1)
Hence both equation actually same
So there can be infinite values of x and y
So there can be infinite values of x and y
For Example
And so on

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.

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