# Quick Question

• Jan 2nd 2010, 12:39 AM
Paymemoney
Quick Question
Hi
Can someone tell me how i would work this out:

Express the following in the form $x+y\sqrt2$ with x and y rational numbers:
$(7+5\sqrt2)^3$

P.S
• Jan 2nd 2010, 12:44 AM
red_dog
Use the formula $(a+b)^3=a^3+3a^2b+3ab^2+b^3$