State, whether the following numbers is rational or not : ( 5 + 5… - Vidyadip

Question

State, whether the following numbers is rational or not : $( 5 + \sqrt5 )( 5 - \sqrt5 )$

✓

Answer

$( 5 + \sqrt5 )( 5 - \sqrt5 )$
$= ( 5 )^2 - ( \sqrt5 )^2$
$ = 25 - 5$
$= 20$
Rational Number

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "[1 Mark Question Answer]" from Rational and Irrational Numbers→Rational and Irrational Numbers — all question types→MATHEMATICS STD 9 question papers→ICSE Board STD 9 question papers→ICSE Board question paper generator→

Similar questions

Express the following in the exponential form$:-2 = \log_2 0.25$

Classify the rational and irrational number from the following:
$\sqrt[3]{3}$

Express the following decimal as a rational number.$0.93$

Write the slope of the line which is: Parallel to the $ y-$axis.

Express the following in the exponential form$:\log _{25} \sqrt{5}=\frac{1}{4}$

Factorise : $a^2- 3a - 40$

Write the inclination of a line which is$: $Parallel to the $ x-$axis.

Expand : $( x + 8 ) ( x + 10 )$

Write the lowest rationalising factor of : $\sqrt24$

Separate the rational and irrational from among the following number:-
$2 . \overline{4}$