Question

Question 1 (iii)
Solve the following pair of linear equations by the substitution method.
3x - y = 3 ; 9x - 3y = 9

Answer 1

3x - y = 3 ... (i)
9x - 3y = 9 ... (ii)
From equation (i), we get
y = 3x - 3 ... (iii)
Substituting the value of y in equation (ii), we get
9x - 3(3x - 3) = 9
9x - 9x + 9 = 9
9 = 9
This is always true.
Hence, the given pair of equations has infinite possible solutions and the relation between these variables can be given by;
y = 3x - 3
Therefore, one of its possible solutions is x = 1, y = 0.