We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website. cookie policy and privacy policy.
 
+0  
 
+1
57
2
avatar+75 

Given that \(a+b=5\) and \(a^2+b^2=15\), find \(a^3+b^3\).

 May 19, 2019
 #1
avatar+5172 
+1

\(a^3 + b^3 = (a+b)(a^2 -ab +b^2)=\\ (a+b)^2 = a^2 + b^2 + 2ab=15+2ab=25\\ 2ab=10\\ ab=5\\ a^3+b^3=5(15-5)=50\)

.
 May 19, 2019
edited by Rom  May 19, 2019
 #2
avatar+75 
0

That was much simpler than what I was thinking

 May 25, 2019

17 Online Users

avatar
avatar
avatar
avatar