a: \(=68\cdot72\cdot49\cdot\left[324-324\right]=0\)

b: \(=\left(1250-1250\right)\cdot\left(1+...+100\right)=0\)

\(a,\left(68\times72\times49\right)\times\left(27\times12-9\times36\right)=\left(68\times72\times49\right)\times0=0\\ b,\left(25\times50-125\times10\right)\times\left(1+2+...+100\right)=0\times\left(1+2+...+100\right)=0\)

a, ( 68 × 72 × 49 ) × ( 27 × 12 − 9 × 36 ) = ( 68 × 72 × 49 ) × 0 =

b, ( 25 × 50 − 125 × 10 ) × ( 1 + 2 + ... + 100 ) = 0 × ( 1 + 2 + ... + 100 ) = 0

91 x 51 + 49 x 163 - 49 x 72

= 91 x 51 + 49 x ( 163 - 72 )

= 91 x 51 + 49 x 91

= 91 x ( 51 + 49 )

= 91 x 100

= 9100

91x51 + 49x163-49x72

=91x51+49x( 163-72)

=91x51+49x91

=91x(51+49)

=91x100

=9100

91 x 51 + 49 x 163 - 49 x 72

= 91 x 51 + 49 x ( 163 - 72 )

= 91 x 51 + 49 x 91

= 91 x ( 51 + 49 )

= 91 x 100

= 9100

nói chung là lên gg mà sợt;vvv

a: \(=81\cdot51+49\cdot81=81\cdot100=8100\)

b: \(=371\left(65+25+10\right)=37100\)

a,81*51+49*153-49*72

= 81*51+49*(153-72)

=81*51+49*81

=81*(51+49)

=81*100

=8100

   35 \(\times\) 49 + 51 \(\times\) 36

= 35 \(\times\) 49 + 51 \(\)\(\times\) (35 + 1)

= 35 \(\times\) 49 + 35 \(\times\) 51 + 51

= (35 \(\times\) 49 + 35 \(\times\) 51) + 51

= 35 \(\times\)( 49 + 51) + 51

= 35 \(\times\) 100 + 51

= 3500 + 51

= 3551

   81 x 51 + 49 x 153 - 49 x 72

= 49 x 2 x 51 + 49 x 153 - 49 x 72

= 49 x 102 + 49 x 153 - 49 x 72

= 49 x ( 102 + 153 - 72 )

= 49 x 183

= 8967

\(\frac{x}{27}=\frac{12}{18}\)

Vì \(\frac{x}{27}=\frac{12}{18}\Rightarrow x\cdot18=27\cdot12\)

\(\Rightarrow x=\frac{27\cdot12}{18}=18\)

\(\frac{35}{49}=\frac{10}{x}\)

Vì \(\frac{35}{49}=\frac{10}{x}\Rightarrow35\cdot x=49\cdot10\)

\(\Rightarrow x=\frac{49\cdot10}{35}=14\)

35 x 49 + 51 x 36 = 35 x 49 + 51 x ( 35+1) =35 x 49 + 51 x 35 + 51 = 35 x ( 49 + 51 ) + 51 = 35 x 100 + 51 = 3500+51 = 3551

=(36-1)x49+51x36

=36x49-1x49+51x36

=36x49-49+51x36

=36x(49+51)-49

=36x100-49

=3600-49

=3551

Tính nhanh 9106×101-9136