bạn lấy máy tính tính nhé

bn tính từng phần nhân chia trước cộng trừ sau!

bấm máy là xog

Bài 1:

a) Ta có:

\(3,2\cdot x+\left(-1,2\right)\cdot x+2,7=-4,9\)

\(\Rightarrow\left[3,2+\left(-1,2\right)\right]\cdot x=\left(-4,9\right)-2,7\)

\(\Rightarrow2x=-7,6\)

\(\Rightarrow x=\left(-7,6\right):2\)

\(\Rightarrow x=-3,8\)

Vậy \(x=-3,8\)

b) Ta có:

-5,6.x+2,9.x-3,86=-9,8

=>[(-5,6)+2,9].x=(-9,8)+3,86

=>(-2,7).x=-5,94

=>x=(-5,94):(-2,7)

=>x=2,3

Vậy x=2,2

Dễ mà. ấn máy tính cũng ra

\(A=-5,13:\left(5\dfrac{5}{28}-1\dfrac{8}{9}.1,25+1\dfrac{16}{63}\right)\)

\(=-5,13:\left(5\dfrac{5}{28}-2\dfrac{13}{36}+1\dfrac{16}{63}\right)\)

\(=5,13:\left[\left(5-2+1\right)+\left(\dfrac{5}{28}-\dfrac{13}{36}+\dfrac{16}{63}\right)\right]\)

\(=5,13:\left(4+\dfrac{1}{14}\right)\)

\(=1,26\)

`A=-5,13:(5 5/28-1 8/9 .1,25+1 16/63)`

`A=-513/100:(145/28-17/9 .5/4+79/63)`

`A=-513/100:(145/28-85/36+79/63)`

`A=-513/100:(355/126+79/63)`

`A=-513/100:57/14`

`A=-63/50`

\(A=-5,13:\left(5\dfrac{5}{28}-1\dfrac{8}{9}.1,25+1\dfrac{16}{63}\right)\)

\(A=-5,13:\left[\left(5-2+1\right)+\left(\dfrac{5}{28}-\dfrac{18}{36}+\dfrac{16}{63}\right)\right]\)

\(A=-5,13:\left(4+\dfrac{1}{14}\right)\)

\(A=-5,13:\left(\dfrac{56}{14}+\dfrac{1}{14}\right)\)

\(A=-5,13:\dfrac{57}{14}\)

\(A=\dfrac{-513}{100}:\dfrac{57}{14}\)

\(A=\dfrac{-513}{100}\times\dfrac{14}{57}\)

\(A=\dfrac{-63}{50}\)

a) \(-5,13:\left(5\frac{5}{28}-1\frac{8}{9}.1,25+1\frac{16}{63}\right)\)

\(=-5,13:\left(\frac{145}{28}-\frac{17}{9}.1,25+\frac{79}{63}\right)\)

\(=-5,13:\left(\frac{145}{28}-\frac{85}{36}+\frac{79}{63}\right)\)

\(=-5,13:\frac{57}{14}\)

\(=-\frac{63}{50}\)

b) \(\left(3\frac{1}{3}.1,9+19,5:4\frac{1}{3}.\left(\frac{62}{75}-\frac{4}{25}\right)\right)\)

\(=\left(\frac{10}{3}.1,9+19,5:\frac{13}{3}\right).\left(\frac{62}{75}-\frac{4}{25}\right)\)

\(=\left(\frac{19}{3}+\frac{9}{2}\right).\frac{2}{3}\)

\(=\frac{65}{6}.\frac{2}{3}\)

\(=\frac{65}{9}\)

 ^...^  ^_^

a) -5,13:(5/5/28-85/36+1/16/63)

     -5,13:(355/126+79/63)

      -5,13:57/14

       =-126

B(19/3+9/2).2/3

65/6.2/3

= 65/9

ngu như cho máy tính đâu

\(A=-5,13:\left(5\frac{5}{28}-1\frac{8}{9}.1,25+1\frac{16}{63}\right)\)

\(A=-5,13:\left(5\frac{5}{28}-\frac{85}{36}+1\frac{16}{63}\right)\)

\(A=-5,13:\frac{57}{14}=-\frac{63}{50}\)

\(B=\left(3\frac{1}{3}.1,9+19,5:4\frac{1}{3}\right).\left(\frac{62}{72}-\frac{4}{25}\right)\)

\(B=\left(\frac{19}{3}+\frac{9}{2}\right).\frac{631}{900}\)

\(B=\frac{65}{6}.\frac{631}{900}=\frac{8203}{1080}\)

dấu * là dấu nhân nha

cái này bn dùng máy tính cho nhanh