## 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: