计算:(-2x+7y)2(-2-5)2(x-3)(x2+9)(x+3)a2+(b-a)(b+a)(3a+1)2(3a-1)2

Question

计算:(-2x+7y)2 (-2-5)2 (x-3)(x2+9)(x+3) a2+(b-a)(b+a) (3a+1)2(3a-1)2

Answer 1

:(-2x+7y)2
=(-2x)²-28xy+(7y)²
=4x²-28xy+49y²
(-2-5)2 =(-7)²=49
(x-3)(x2+9)(x+3)
=(x-3)(x+3)(x²+9)
=(x²-9)(x²+9)
=x的4次方-81
a2+(b-a)(b+a)
=a²+b²-a²
=b²
(3a+1)2(3a-1)2
=[(3a+1)(3a-1)]²=(9a²-1)²=81a的4次方-18a²+1