Xét tử số 37x13-13=( 37x12+37 )-13 
Bằng 37x12+24 
Suy ra:37x13-13/24+37x12 = 37x12+24/24+37x12 
Vậy bằng 1

37 x 13 - \(\frac{13}{24}\) + 37 x 12

=  37 x ( 13 + 12) - \(\frac{13}{24}\)

=  37 x 25 - \(\frac{13}{24}\)

=      925 - \(\frac{13}{24}\)

=       \(\frac{22187}{24}\)

\(37\times13-\frac{13}{24}+37\times12\)

\(=37\times13+37\times12-\frac{13}{24}\)

\(=37\times\left(13+12\right)-\frac{13}{24}\)

\(=37\times15-\frac{13}{24}\)

\(=505-\frac{13}{24}\)

\(=\frac{505\times24-13}{24}\)

\(=\frac{12107}{24}\)

1, =35 x 77-35 x 12+35x35-35 x 18 suy ra =35 x(77-12+35-18)=35 x 82=2870.

2, =2014 x (100-1)=201400-2014=199386.

3,=35x12+65x12+65=12x(65+35)+65=1200+65=1265.

4.=\(\frac{13\times\left(37-1\right)}{12\times\left(37+2\right)}\)=\(\frac{13\times36}{12\times39}=\frac{13\times3\times12}{12\times3\times13}=1\)

tck nha bạn

\(\frac{37\times13-13}{24+37\times12}\)

\(=\frac{27\times12+37-13}{24+37\times12}\)

\(=\frac{24+37\times12}{24+37\times12}\)

\(=1\)

\(\dfrac{7}{5}:x=\dfrac{25}{37}.\dfrac{13}{21}+\dfrac{2}{7}.\dfrac{13}{21}\)

\(\dfrac{7}{5}:x=\dfrac{13}{21}.\left(\dfrac{25}{37}+\dfrac{2}{7}\right)\)

\(\dfrac{7}{5}:x=\dfrac{1079}{1813}\)

\(x=\dfrac{12691}{5395}\)