Question

If a=3+2√2 then find the value of a2-6a​

Answer 1

Answer: -1

Step-by-step explanation:

a^2-6a

(3+2-/2)^2 - 6(3+2_/2)

9+8+12_/2 - 18-12_/2

-1

Answer 2

Answer:

$\sf{The \ value \ of \ a^{2}-6a \ is \ -1.}$

Given:

$\sf{\leadsto{a=3+2\sqrt2}}$

To find:

$\sf{The \ value \ of \ a^{2}-6a.}$

Solution:

$\sf{\leadsto{a^{2}-6a}}$

$\sf{Substitute \ a=3+2\sqrt2}$

$\sf{\leadsto{(3+2\sqrt2)^{2}-6(3+2\sqrt2)}}$

$\sf{\leadsto{9+12\sqrt2+8-18-12\sqrt2}}$

$\sf{\leadsto{-1}}$

$\sf\purple{\tt{\therefore{The \ value \ of \ a^{2}-6a \ is \ -1.}}}$

_____________________________

$\sf\blue{Extra \ information:}$

$\sf{Identities:}$

$\sf{1. \ (a+b)^{2}=a^{2}+2ab+b^{2}}$

$\sf{2. \ (a-b)^{2}=a^{2}-2ab+b^{2}}$

$\sf{3. \ a^{2}-b^{2}=(a+b)(a-b)}$

$\sf{4. \ a^{2}+b^{2}=(a+b)^{2}-2ab}$

$\sf{5. \ a^{2}+b^{2}=(a-b)^{2}+2ab}$

$\sf{6. \ (a+b)^{2}=(a-b)^{2}+4ab}$

$\sf{7. \ (a-b)^{2}=(a+b)^{2}-4ab}$

$\sf{8. \ (a+b)^{2}+(a-b)^{2}=2(a^{2}+b^{2})}$

$\sf{9. \ (a+b)^{2}-(a-b)^{2}=4ab}$