Question

Solve the following pair of linear equations by the substitution method.

s – t = 3

`s/3 + t/2 = 6`

Answer 1

s – t = 3     ...(1)

`s/3 + t/2 = 6`

From (1), we obtain

s = t + 3     ...(3)

Substituting this value in equation (2), we obtain

`(t + 3)/3 + t/2 = 6`

2(3 + t) + 3(t) = 6 × 6

6 + 2t + 3t = 36

5t = 30

`t = 30/5`

t = 6

Substituting in equation t = 6(3), we obtain

s = 3 + 6

s = 9

∴ s = 9, t = 6