$(\sqrt{61}\pm 3a)^3$

Algebra Level 2

If $a=\sqrt{7}$ , what is the value of $\begin{aligned} & \left((\sqrt{61}+3a)^3-(\sqrt{61}-3a)^3\right)^2 \\ & -\left((\sqrt{61}+3a)^3+(\sqrt{61}-3a)^3\right)^2? \end{aligned}$

31 29 32 30

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Branislav Dinic
Mar 17, 2014

Well I use the real world solving thingy -). I assign (sqrt(61)+3a)^3 to a, and (sqrt(61)-3a)^3 to b. Then I got -4ab of that expression. And using calculator I got a= 3905.124202, b = -0.002048383, and the total result was 31.9967~32

cool bro...

MOHD NAIM MOHD AMIN - 7 years ago

( 61 ± 3 a ) 3 (\sqrt{61}\pm 3a)^3 ( 6 1 ​ ± 3 a ) 3

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$(\sqrt{61}\pm 3a)^3$