Bài 1:

b) \(71+65.4=\frac{x+140}{x}+260\)

\(\Rightarrow331=\frac{x+140}{x}+260\)

\(\Rightarrow\frac{x+140}{x}=71\)

\(\Rightarrow x+140=71x\)

\(\Rightarrow71x-x=140\)

\(\Rightarrow70x=140\)

\(\Rightarrow x=2\)

Vậy ...

c) \(7:\left(\frac{3,8.x}{19}+3\right)=1,75\)

 \(\frac{3,8.x}{19}+3=4\)

\(\frac{3,8.x}{19}=1\)

\(3,8.x=19\)

\(x=5\)

vaayj ...

\(7:\left(\frac{3,8\times x-57}{19}+3\right)=1,75\)

=> \(\frac{3,8\times x-57}{19}+3=7:1,75\)

=> \(\frac{3,8\times x-57}{19}+3=4\)

=> \(\frac{3,8\times x-57}{19}=4-3=1\)

=> \(3,8\times x-57=19\)

=> \(3,8\times x=19+57=76\)

=> \(x=76:3,8=20\)

Vậy x = 20.

a: Ta có: \(\left(x-7\right)\times22=\left(5\times x\right)+33\)

=>22x-154=5x+33

=>22x-5x=154+33

=>17x=187

=>x=11

b: TA có: \(7,75-\left(0,5\times x:5-6,2\right)=5\)

=>\(0,1\times x-6,2=7,75-5=2,75\)

=>\(0,1\times x=6,2+2,75=8,95\)

=>x=8,95:0,1=89,5

c: \(7:\left(3,8\times x-\frac{57}{19}+3\right)=1,75\)

=>\(7:\left(3,8\times x\right)=1,75\)

=>\(3,8\times x=7:1,75=4\)

=>\(x=\frac{4}{3,8}=\frac{20}{19}\)

Bạn cho minh cách lam duoc k

\(7:\left(\dfrac{3,8\times y-57}{19}+3\right)=1,75\)

\(\Rightarrow\left(\dfrac{3,8\times y-57}{19}+3\right)=7:1,75\)

\(\Rightarrow\dfrac{3,8\times y-57}{19}+3=4\)

\(\Rightarrow\dfrac{3,8\times y-57}{19}=4-3\)

\(\Rightarrow\dfrac{3,8\times y-57}{19}=1\)

\(\Rightarrow3,8\times y-57=1\times19\)

\(\Rightarrow3,8\times y-57=19\)

\(\Rightarrow3,8\times y=19+57\)

\(\Rightarrow3,8\times y=76\)

\(\Rightarrow y=76:3,8\)

\(\Rightarrow y=20\)

\(7:\frac{5.8.x-57}{19+3}=7.\frac{22}{40x-57}=1775\)

<=> \(\frac{154}{40x-57}=1775=>x=\frac{154+1775.57}{40}\)

X nằm trong khoảng tu 0 den 7/3 because X<(7x100)/57