(2+3.15+5.87)X(3.15+5.87+7.32)—(2+3.15+5.87+7.32)X(3.15+5.87)要简便
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(2+3.15+5.87)X(3.15+5.87+7.32)—(2+3.15+5.87+7.32)X(3.15+5.87)要简便
(2+3.15+5.87)X(3.15+5.87+7.32)—(2+3.15+5.87+7.32)X(3.15+5.87)要简便
(2+3.15+5.87)X(3.15+5.87+7.32)—(2+3.15+5.87+7.32)X(3.15+5.87)要简便
(2+3.15+5.87)X(3.15+5.87+7.32)—(2+3.15+5.87+7.32)X(3.15+5.87)
=2×(3.15+5.87+7.32)+(3.15+5.87)×(3.15+5.87+7.32)—2×(3.15+5.87)-(3.15+5.87+7.32)×(3.15+5.87)
=2×(3.15+5.87+7.32)-2×(3.15+5.87)
=2×7.32
=14.64
(2+3.15+5.87)X(3.15+5.87+7.32)—(2+3.15+5.87+7.32)X(3.15+5.87)
=(2+3.15+5.87)X(3.15+5.87)+(2+3.15+5.87)X7.32-(2+3.15+5.87)X(3.15+5.87)-7.32X(2+3.15+5.87)
=0
设3.15+5.87为a,3.15+5.87+7.32为b
原式=(2+a)×b-(2+b)×a
=2b+ab-2a-ab
=2b-2a
=2×7.32
=14.64
将2+3.15+5.87+7.32作为一个统一体,设为A,那么整个计算公式就变化成了
(A-7.32)×(A-2)- A×(A-2-7.32)=A2-9.32A+14.64-(A2-9.32A)=14.64
注明一下:A2表示A的平方。
2+3.15=a。3.15+5.87=b
(2+3.15+5.87)X(3.15+5.87+7.32)—(2+3.15+5.87+7.32)X(3.15+5.87)=(a+5.87)X(b+7.32)—(a+5.87+7.32)Xb=5.87b+7.32a+5.87X7.32-7.32b=5.87(3.15+5.87)+7.32(2+3.15)-7.32(3.15+5.87)=5.87(3.15+5.87)-7.32(5.87-2)=5.87X(9.02-7.32)+7.32X2