Question:
The equation 2x+ 5y = 7 has a unique solution, if x and y are
(a) natural numbers
(b) positive real numbers
(c) real numbers
(d) rational numbers
Solution:
(a) In natural numbers, there is only one pair i.e., (1, 1)
which satisfy the given equation but in positive real numbers, real numbers and rational numbers there are many pairs to satisfy the given linear equation.