radicals and rational exponents

[subdocwife731]

I am have a lot of trouble with this problem. Any assistance would be great.

( 3- 2?7)(3+2?7)

Does anyone know how to do this?

 

[Denis]

Hint: [a * sqrt(b)] * [a * sqrt(b)] = a^2 * b

 

[Vernon]

Multiplying this out you should find the square roots \(\displaystyle (3 \times -2\sqrt(7) + 3 \times 2\sqrt(7))\) cancel each other out so you're left with 3 x 3 and \(\displaystyle -2\sqrt(7) \times 2\sqrt(7)\)

 

[subdocwife731]

GREAT! Thanks a bunch

 

[Mrspi]

I am have a lot of trouble with this problem. Any assistance would be great.

( 3- 2?7)(3+2?7)

Does anyone know how to do this?

I'd hope you'd look at this problem and say to yourself "Gee...that's just like (a + b)(a - b), and I KNOW that gives me a[sup:30boyf96]2[/sup:30boyf96] - b[sup:30boyf96]2[/sup:30boyf96]. So, it ought to be 3[sup:30boyf96]2[/sup:30boyf96] - (2 sqrt(7))[sup:30boyf96]2[/sup:30boyf96]."

Then, take it from there.

 

[masters]

Glad you cleared that up, mrspi. Don't know what was going on with those other posts.