Question

已知a^2+ab=3,ab+b^2=1,试分别求a^2+2ab+b^2,a^-b^2的值.

Answer 1

a^2+2ab+b^2

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

=3+1

4

a^2=3-ab,b^2=1-ab

a^2-b^2

=3-ab-(1-ab)

=3-ab-1+ab

=2