<s>[INST] Help solve this Problem Given that $a +b +c =5$ and $ab +ac +bc=$5, what is the value of $a^2+b^2+c^2$? 
 [/INST] $(a+b+c)^2=a^2+b^2+c^2+2(ab+bc+ca)\Rightarrow a^2+b^2+c^2=(a+b+c)^2-2(ab+bc+ca)=25-10=15$
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