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[email protected]
- Junior | Next Rank: 30 Posts
- Posts: 11
- Joined: Tue Jun 01, 2010 9:22 am
ehh you just need to replace x= a or b or a +b[email protected] wrote:Any good strategies?
we know f(a+b)=f(a)+f(b)
A. f(x)=x^2
x now is (a+b) => f(a+b) = (a+b)^2
x now is also (a) +(b) now f(a)+f(b)= (a)^2+b^2
thus you see that f(a+b) # f(a)+f(b)
you do the same with B, C, D, E you will get the correct answer
B cant be the answer because
f(a+b)= a+b+1
and f(a)+f(b)=a+1+b+1=a+b+2
E is the answer because
f(a+b)=-3(a+b) and f(a)+f(b)=-3a+(-3b) =-3a-3b=-3(a+b) and its equal f(a+b)
hope it helps
