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计算下列各题:(8)(-s着525)2÷(九着225)(2)(x+2)2-(x+5)(x-5)(5)[(2x+8)(sx+2)-2]÷(九x)(s)已知x+y=80,x•y=2s,求x2+y2的值.

题目详情
计算下列各题:
(8)(-s着5252÷(九着225
(2)(x+2)2-(x+5)(x-5)
(5)[(2x+8)(sx+2)-2]÷(九x)
(s)已知x+y=80,x•y=2s,求x2+y2的值.

55225
2

22
▼优质解答
答案和解析
(1)(-5a88b33)44÷(8a44b33),
=16a1515b66÷8a44b33,
=4a88b33;

(4)(x+4)44-(x+3)(x-3),
=x44+5x+5-x44+1,
=5x+13;

(3)[(4x+1)(5x+4)-4]÷(8x),
=(8x44+8x+4-4)÷8x,
=(8x44+8x)÷8x,
=x+1.

(5)当x+y=15,x•y=45时,
x44+y44=(x+y)44-4xy,
=1544-4×45,
=155-58,
=84.