作业帮19×27+19×23+190X5简算
19×27+19×23+190X5简算
2.4X5+7x=19
3x-4x5二19 解方程
(25—5x2)x(19-5x2)x5
2/1X3+2/3X5+2/5x7+.+2/19x21
1/1X3+1/3X5+1/5X7...1/17X19+1/19X21=
19分之x-7=30分之x+30x5解方程
1×3x5+3×5×7+5×7×9+……+17×19×21
(2X2)/1X3+(4X4)/(3X5)+(6X6)/(5X7)+...+(20X20)/(19X21)==?
2/1X3+2/3X5+2/5x7+.+2/19x21全过程（最好带原因）,
4x+27=63 4x+9X3=63 3x-8=19 3x-2X4=19 6x+4x5=68 12x-7X2=82 6x
27度17'32"X5+12度34'51"