# Tamilnadu Board Class 9 Maths Solutions Chapter 2 Real Numbers Ex 2.7

## Tamilnadu State Board Class 9 Maths Solutions Chapter 2 Real Numbers Ex 2.7

Question 1.
Rationalise the denominator

Solution:

Question 2.
Rationalise the denominator and simplify

Solution:

Multiply the numerator and denominator by the rationatising factor (√27 + √18)

Question 3.
Find the value of a and b if $$\frac{\sqrt{7}-2}{\sqrt{7}+2}=a \sqrt{7}+b$$.
Solution:

Question 4.
If x = √5 + 2 , then find the value of $$x^{2}+\frac{1}{x^{2}}$$ .
Solution:
If x = √5 + 2

Question 5.
Given √2 = 1.414, find the value of $$\frac{8-5 \sqrt{2}}{3-2 \sqrt{2}}$$ (to 3 places of decimals).
Solution: