Question

已知a加b等于负三,ab等于一,求a的平方加b的平方等于

Answer 1

由题意可得：a+b=-3,ab=1

a^2+b^2

=a^2+b^2+2ab-2ab

=(a+b)^2-2ab

=(-3)^2-2*1

=9-2

=7