(1+0.23+0.34)*(0.23+0.34+0.65)-(1+0.23+0.34+0.65)*(0.23+0.34)不要设方程,用递等式回答.

Question

(1+0.23+0.34)*(0.23+0.34+0.65)-(1+0.23+0.34+0.65)*(0.23+0.34) 不要设方程,用递等式回答.

Answer 1

1
设：1+0.23+0.34=a,0.23+0.34+0.65=b
a-b=1-0.65=0.35
则有：ab-(a+0.65)(b-0.65)
=ab+0.65a-0.65b+0.65x0.65
=0.65(0.65+a-b)
=0.65(0.65+0.35)
=0.65
2
（1+0.23+0.34）×(0.23+0.34+0.65)-(1+0.23+0.34+0.65)×(0.23+0.34)
=1×(0.23+0.34+0.65)+(0.23+0.34)×(0.23+0.34+0.65)-1×(0.23+0.34)-(0.23+0.34+0.65)×(0.23+0.34)
=1×(0.23+0.34+0.65)-1×(0.23+0.34)
=0.65
还有一种直接算出;
(1+0.23+0.34)*(0.23+0.34+0.65)-(1+0.23+0.34+0.65)*(0.23+0.34) = 0.65
【很麻烦】