Question

If the replacement set is the set of natural numbers (N), then find the solution set for the given inequation $1+9x\ge x+81$........[3 marks]

Answer 1

Given: $1+9x\ge x+81$ $\Rightarrow 9x-x\ge 81-1$ $\Rightarrow 8x\ge 80$......[1 mark] On dividing both sides by 8 in the inequation; $\Rightarrow x\ge \frac{80}{8}$ $\Rightarrow x\ge 10$........[1 mark] Since, the replacement set is a set of natural numbers, therefore {$x:x\ge 10,x\epsilon N$}......[1 mark]