Question

if a =1 +√7, find -6/a​

Answer 1

- 6  

-------------------  

1 + √7  

- 6 [ 1 - √7 ]  

--------------------------------  

[ 1 + √7 ] [ 1 - √7 ]  

6 √7 - 6  

------------------  

- 6  

1 - √7

Answer 2

Answer:

$1-\sqrt{7}$

Step-by-step explanation:

a =1 +√7, find -6/a​

$\frac{-6}{a} = \frac{-6}{1+\sqrt{7} }$

$\frac{-6.(1-\sqrt{7}) }{(1+\sqrt{7} ).(1-\sqrt{7}) }$

• $(a-b).(a+b)=a^{2} -b^{2}$

= $\frac{-6.(1-\sqrt{7}) }{1-7 }$

=$\frac{-6.(1-\sqrt{7}) }{-6 }$

= $1-\sqrt{7}$