`30,5=4,5 xx x+12,5`

`4,5xx x=30,5-12,5=18`

`x=18:4,5=4`

___________________________

`(x+4,5)xx2,5=15`

`x+4,5=15:2,5=6`

`x=6-4,5=1,5`

______________________________

`1,26:x+2,34:x=5`

`(1,26+2,34):x=5`

`3,6:x=5`

`x=3,6:5=0,72`

30,5 = 4,5 x X + 12,5 

4,5 x X = 30,5 - 12,5

4,5 x X = 18

X = 18 : 4,5

X = 4

[ X + 4,5 ] x 2,5 = 15 

X + 4,5 = 15 : 2,5

X + 4,5 = 6

X = 6 - 4,5

X = 1,5

1,26 : X + 2,34 : X =5

3,6 : X = 5

X = 3,6 : 5

X = 0,72 

hrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

96,73 * 5348 = 517 312,04

36,98 : 5,32 = 6,95 (dư 0,60)

48,54 * 89,6 = 4349,184

998,6 : 5,3 = 188,41 (dư 2,7)

873,7 : 63 = 13,86 ( Dư 52 )

5,217 * 8,62 = 44,97054

a) \(x+1,23\div3=1,845\)                                                       c) Không rõ 

\(x+0,41=1,845\)

\(x=1,845-0,41\)

\(x=1,435\)

b) \(x\times\frac{1}{4}+x\times\frac{1}{5}+x\times2=19,6\)                                 d) \(x+3\frac{1}{2}+20=24\frac{1}{4}\)

\(x\times\left(\frac{1}{4}+\frac{1}{5}+2\right)=19,6\)                                                  \(x+\frac{7}{2}+20=\frac{97}{4}\)

\(x\times\frac{49}{20}=19,6\)                                                                          \(x+\frac{47}{2}=\frac{97}{4}\)

\(x=19,6\div\frac{49}{20}\)                                                                          \(x=\frac{97}{4}\div\frac{47}{2}\) 

\(x=8\)                                                                                               \(x=\frac{97}{94}\)

x + 1.23 = 5.535

x = 4.305

\(a,34,9+62,17-43,3+15,1-12,17-56,7\\ =\left(34,9+15,1\right)+\left(62,17-12,17\right)-\left(43,3+56,7\right)\\ =50+50-100\\ =100-100\\ =0\\ b,1,25\times2,5\times80\times40\\ =\left(1,25\times80\right)\times\left(2,5\times40\right)\\ =100\times100\\ =10000\)

x+2,47=5,09

x=5,09-2,47

x=2,62

8,23-x=4,56

x=8,23-4,56

x=3,67

a) x + 2,47 = 5,09

x = 5,09 - 2,47

x = 2,62

8,23 - x = 4,56

x = 8,23 - 4,56

x = 3,67

\(\)30 , 5 x 19 , 7 + 2 , 43 x 305 + 6 , 1 x 56 x 5 

= 30 , 5 x 19 , 7 + 2 , 43 x ( 10 x 30 , 5 ) + 6 , 1 x 280 

= 30 , 5 x 19 , 7 + 24 , 3 x 30 , 5 + 6 , 1 x 280 

= 30 , 5 x ( 19 , 7 + 24 , 3 ) + 6 , 1 x 280 

= 30 , 5 x 44 + 6 , 1 x 280 

= 30, 5  x 44 + 6 , 1 x 5 x 56 

= 30 , 5 x 44 + 30 , 5 x 56

= 30 , 5 x ( 44 + 56 ) 

= 30 , 5 x 100

= 305

Tham khảo nha !!! Học tốt !!!  

305

Chúc bạn hok tốt!

^_^ 

kết thúc,ko trả lời mà có trả lời cũng ko tích

2.34 x 1.3 + 23.4 x 0.87

= 2.34 x 1.3 + 2.34 x 8.7

= 2.34x( 1.3+8.7 )

= 2.34 x 10

= 23.4

2,34 x 1,3 + 23,4 x 0,87 

= 2,34 x1,3 + 2,34 x 8,7

=2,34 x (1,3 + 8,7)

=2,34 x 10

=23,4