Do quên nhân chữ số 0 của số 2.07 nên tích tăng lên thêm 9,45

Từ đây ta có phương trình

A*2,7=A*2,07+9,45

<=>2,7*A-2,07*A=9,45

<=>0,63*A=9,45

<=>A=15

4.85+12.5 x X=5.85

         12.5 x X = 5.85 - 4.85

          12.5 x X = 1

                    X = 1 : 12.5

                    X = 0.08

4.85+12.5 x X=5.85

12.5 x X=5.85-4.85

12.5 x X=1

X=1:12.5

X=0.08

\(17.93+116.83+17.23.\)

\(=17\left(93+23\right)+116.83.\)

\(=17.116+116.83.\)

\(=116\left(17+83\right).\)

\(=116.100=11600.\)

Vậy.....

17 . 93 + 116 . 83 +17 . 23

= 17 . (93 + 23) + 116 . 83

= 17 . 116 + 116 . 83

= 116 . (17 + 83)

= 116 . 100

= 11600

45 x (X + 25.38 )= 45 x (2.07 + 25.38 )

\(\Rightarrow\)X +25.38 = 2.07 + 25.38

\(\Rightarrow\)X = 2.07 + 25.38 - 25.38

\(\Rightarrow\)X = 2.07

các bạn nhớ cho mk nha 

\(136\cdot23+136\cdot27-40\cdot36\)

\(=136\cdot\left(23+17\right)-40\cdot36\)

\(=136\cdot40-40\cdot36\)

\(=40\cdot\left(136-36\right)\)

\(=40\cdot100=4000\)

\(17\cdot93+116\cdot83+17\cdot23\)

\(=17\cdot\left(93+23\right)+116\cdot83\)

\(=17\cdot116+116\cdot83\)

\(=116\cdot\left(17+83\right)\)

\(=116\cdot100=11600\)

\(136.23+136.17-40.36\)

\(=136.\left(23+17\right)-40.36\)

\(=136.40-40.36\)

\(=40.\left(136-36\right)\)

\(=40.100\)

\(=100\)

\(17.93+116.83+17.23\)

\(=17.\left(93+23\right)+116.83\)

\(=17.116+116.83\)

\(=116\left(17+83\right)\)

\(=116.100\)

\(=11600\)

c1

=2/3:(3/4+1/4)

=2/3:1

=2/3x1/1

=2/3

c2

tinh như bình thuong