(1)
(a+b)²
=a²+b²+2ab
=26+2x5
=36
a+b=±√36=±6
(2)
(a-b)²
=a²+b²-2ab
=26-2x5
=16
∵a>b
∴a-b>0
即a-b=√16=4
于是
a^2-b^2
=(a+b)(a-b)
=±6x4
=±24
(1)
(a+b)²
=a²+b²+2ab
=26+2x5
=36
a+b=±√36=±6
(2)
(a-b)²
=a²+b²-2ab
=26-2x5
=16
∵a>b
∴a-b>0
即a-b=√16=4
于是
a^2-b^2
=(a+b)(a-b)
=±6x4
=±24