请问数学： （x-1.4020）÷x=+0.0072，这题目是否这样计算 （1.4020-x）÷x=0.0072 1.4020=0.0072？(32.55x32

• 32.55x32.55的简便计算方法
• 计算x²－y²－x－¼
• 2004.05X1997．05－2001．05x1999．05的简便计算
• 2012.25x2013.75－2010.25x2015.75＝？简便计算

32.55x32.55的简便计算方法

解:32.55X32.55

=32.55²

=(30十2.55)²

=30²十2X30X2.55十2.55²

=900十30X5.10十2.55²

=900十153.0十(2十0.55)²

=1053十4十2X2X0.55十0.55²

=1057十4X0.55十0.3025

=1057十2.20十0.3025

=1059.20十0.3025

=1059.3025

计算x²－y²－x－¼

原式=(x²-x-¼)-y²

=(x-½)²-y²

=(x+y-½)(x-y-½)

2004.05X1997．05－2001．05x1999．05的简便计算

2004.05X1997.05－2001.05x1999.05

=2004.05X1997.05－2001.05x1997.05-2001.05x2

=（2004.05-2001.05）x1997.05-4002.1

=3x1997.05-4002.1

=5991.15-4002.1

=1989.05

2012.25x2013.75－2010.25x2015.75＝？简便计算

(2010.25+2) X 2013.75 - 2010.25 X 2015.75

=2010.25 X 2013.75 + 2 X 2013.75 - 2010.25 X 2015.75

=2010.25 X( 2013.75 - 2015.75) + 2 X 2013.75

= 2 X 2013.75- 2 x 2010.25

=2 X 3.5

=7