Đáp án cần chọn là: D

x–35=−90−|−78|

x–35=−90−78

x–35=−168

x=−168+35

x=−133

a) 87 x (-78) + 78 x 31 - 78 x (-156)

= (-87 + 31 + 156) x 78

=  100 x 78

= 7800

b) -178 x (-35 - 78) - 78 x (178 + 35)

= -178 x (-113) - 78 x 213

= 20114 - 16614

= 3500

q) $x:11-21=35$

$x:11=35+21$

$x:11=56$

$x=56\times11$

$x=616$

b) $78-x:11=19$

$x:11=78-19$

$x:11=59$

$x=59\times11$

$x=649$

78/78 < 79/78

35/145 > 35/175

2017/2018 < 2018/2019

K mk nhé

\(\frac{78}{78}< \frac{79}{78}\)

\(\frac{35}{145}>\frac{35}{175}\)

\(\frac{2017}{2018}< \frac{2018}{2019}\)

Hok tốt!

Ko chắc câu cuối nha~!

a , 280
b , 390
HT

a) 78=2.3.13

   39=3.13

ƯCLN(78,39)=3X13=39;ƯC(78,39)=39;BCNN(78,39)=78;BC(78,39)=78

B)125=5^3

    35=5.7

UCLN(125,35)=5;ƯC(125;35)=5;BCNN(125,25)=875;BC(125;25)=875

a)

UCLN(78,39) = 39 (vì 78 chia hết cho 39)

=> ƯC(78,39) = Ư(39) = {1;3;13;39}

BCNN(78,39) = 78 (vì 78 chia hết cho 39)

=> BC(78,39) = B(78) = {0;78;156;...}

b)

125 = 5³

35 = 5 x 7

=> UCLN(125,35) = 5

=> ƯC(125,35) = Ư(5) = {1;5}

=> BCNN(125,35) = 5³ x 7 = 875

=> BC(125,35) = B(875 = {0;875;1750;...}

a)ƯCLN(78;39)=39

ƯC(78;39)=Ư(39)={1;3;13;39}

BCNN(78;39)=78

BC(78;39)=B(78)={0;78;156;234;...}

b)ƯCLN(125;35)=5

ƯC(125;35)=Ư(5)={1;5}

BCNN(125;35)=875

BC(125;35)=B(875)={0;875;1750;2625;...}

14/21>14/36

15/35>14/35

22/21>22/46

78/90>78/100

14/21 > 14/36

15/5 > 14/35

22/21 >  22/46

78/90  >   78/100