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?
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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!
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