It is important to know rational expression because we come across rational expressions most of the time in the real world, often without even realizing it.
Example: you may want to know how much of a 25% chemical solution need to be added to 1L of water to produce a 10% solution.
Ans: Equation:
solution + water = solution
0.25x + 0*1 L = 0.10(x+1)
Multiply the above equation by 100 to get:
25x + 0 = 10x + 10
15x = 10
x = 2/3 Liter (amt. of 25% solution in the mixture)
