Question

Simplify the final answer:
(4 + sqrt(7)) * (4 - sqrt(7))

Answer 1

FOIL.

Answer 2

9.

Answer 3

\[(4 + \sqrt{7}) * (4 - \sqrt{7}) \]

Answer 4

16-7=9.

Answer 5

\[(a-b)(a+b)=a^2-b^2\]

Answer 6

\[(4)^2-(\sqrt{7})^2=16-7=9 \]

Answer 7

as we know that \[(a-b)(a+b)=a^2-b^2\]
hence
\[(4+sqrt7)(4-sqrt7)\]
\[((4)^2-(sqrt7)^2\]
\[16-7\] since 4^2=16 and sqrt7^2=7
\[9\]
got it

Answer 8

did you really say FOIL?

Answer 9

thanks kushashwa23 - makes complete sense!