Thread: Algebra question

Hi, I got this question wrong in an assignment I did and was wondering how you get the answer.

Expand and simplify (x-(1/3y)+(2/5z))^2?

The answer is apparantly x^2 + 1/9y2 + 4/25z^2 - 2/3xy + 4/5xz - 2/15yz But how do I get that?

Originally Posted by brumby_3

Hi, I got this question wrong in an assignment I did and was wondering how you get the answer.

Expand and simplify (x-(1/3y)+(2/5z))^2?

The answer is apparantly x^2 + 1/9y2 + 4/25z^2 - 2/3xy + 4/5xz - 2/15yz But how do I get that?

Use following formula.
(a+b+c)^2 = a^2 + b^2 + c^2 +2ab +2bc +2ac.

Originally Posted by sa-ri-ga-ma

Use following formula.
(a+b+c)^2 = a^2 + b^2 + c^2 +2ab +2bc +2ac.

So it would be x^2 - (1/3y)^2 + (2/5z)^2 + (2*x*-(1/3y)) + (2*(-1/3y)*(2/5z)) + (2*x*(2/5z))

???

OH! and then you ^2 everything - I can see it now, thanks a lot!