0 votes 0 votes Let $a, b, c$ and $d$ be real numbers such that $a+b=c+d$ and $ab=cd$. Prove that $a^n+b^n=c^n+d^n$ for all positive integers $n$. Quantitative Aptitude isi2017-pcb-a quantitative-aptitude number-system descriptive + – go_editor asked Sep 19, 2018 • retagged Nov 19, 2019 by Lakshman Bhaiya go_editor 326 views answer comment Share Follow See 1 comment See all 1 1 comment reply `JEET commented Nov 20, 2019 reply Follow Share https://math.stackexchange.com/questions/2375092/if-ab-cd-then-abcd-is-not-prime-for-integers-a-b-c-d-0 0 votes 0 votes Please log in or register to add a comment.