个正方体的表面积是 。
二、判断。5分
1、长方体最少有两个面是正方形。·····················( )
2、正方体棱长扩大了3倍,它的占地面积就扩大9倍。············( )
3、因为2²=2×2,所以,2³=2×3。·····························( )
4、一根绳子分成4段,每段占全长的。························( )
5、两个不同的方程可能有相同的解。····························( )
三、解方程。12分
1.9x-0.4x=60 0.3x+2.7=5.94
4.5x÷3=0.9 (7-1.4)x+5=7.8