Question

已知实数a,b满足（a+b)(a+b)=1,(a-b)(a-b)=25,求a*a+b*b+ab的值

Answer 1

2(a*a+b*a)

=（a+b)(a+b)+(a-b)(a-b)

=1+25

=26

a*a+b*b=13

4ab

=（a+b)(a+b)-(a-b)(a-b)

=1-25

=-24

ab=-6

a*a+b*b+ab

=13-6

=7