Hi

Can someone tell me how i would work this out:

Express the following in the form$\displaystyle x+y\sqrt2$ with x and y rational numbers:

$\displaystyle (7+5\sqrt2)^3$

P.S

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- Jan 2nd 2010, 12:39 AMPaymemoneyQuick Question
Hi

Can someone tell me how i would work this out:

Express the following in the form$\displaystyle x+y\sqrt2$ with x and y rational numbers:

$\displaystyle (7+5\sqrt2)^3$

P.S - Jan 2nd 2010, 12:44 AMred_dog
Use the formula $\displaystyle (a+b)^3=a^3+3a^2b+3ab^2+b^3$