Question

Stiind ca a+b=4 si a×b=2, calculati a²+b² 

Answer 1

$a+b=4 \ \ |^2 \\\\ (a+b)^2=4^2 \\\\ a^2+2ab+b^2=16\\\\ a^2+b^2=16-2*2 \\\\ a^2+b^2=16-4 \\\\ \boxed{a^2+b^2=12}$