数学问题
用简便方法计算
1.222^2*9-1.333^2*4+1.333*8-1.222*12
怎么做啊???
参考答案:原式=(1.222*3-1.333*2)*(1.222*3+1.333*2)+4(1.333*2-1.222*3)
=(1.222*3-1.333*2)*(1.222*3+1.333*2-4)
=(3.666-2.666)*(3.666+2.666-4)
=1+2*0.666=2.332
用简便方法计算
1.222^2*9-1.333^2*4+1.333*8-1.222*12
怎么做啊???
参考答案:原式=(1.222*3-1.333*2)*(1.222*3+1.333*2)+4(1.333*2-1.222*3)
=(1.222*3-1.333*2)*(1.222*3+1.333*2-4)
=(3.666-2.666)*(3.666+2.666-4)
=1+2*0.666=2.332