a) 5.4^x + 4^2+x= 336

5.4^x + 4² . 4^x = 336

4^x . (5 + 4²) = 336

4^x . 21 = 336  

4^x = 336 : 21

4^x = 16

4^x = 4²

x = 2

b)$x$ là bội của $11$ và $10<x<40$.

Các bội của $11$ là: $0;11;22;33;44;55;\dots$

Mà $10<x<40$

Vậy $x\in \{11;22;33\}$.

a) 571+216+129+124

= (571+129)+(216+1)

= 700+340

= 1040

b) 27.74+26.27−355

$=27.(74+27)-355$

$=27.100-355$

$=2700-355$

$=2345.$

c)100:{250:[450−(4.53−22.25)]}

$=100:\{250:[450-(4.125-4.25)]\}$

$=100:[250:(450-400)]$

$=100:(250:50)$$=100:5=20.$

100:{250:[450−(4.53−22.25)]}

a)các số chia hết cho 2 là: 320;4914;90

b)các số chia hết cho 5 là: 320;2315;90

c)các số chia hết cho 3 là: 90;543;4914

d)các số chia hết cho cả 2;3;5;9 là: 90

First, my family always have breakfast together. We often eat bread or noodles and share our plan for the day while eating. Second, we watch our favourite film on TV together every Saturday evening. We watch a film and share snacks. Then, we exchange opinions after the film. Third, on the second Sunday of the month, we visit our grandparents. When coming to our grandparents’ house, we usually do some housework for them and have lunch with them. They look really happy when talking and eating with us.
 

a] 131,27 + 92,8 = 224,07

b. 23 - 21,58 = 1,42

c. 2,09 x 3,4 = 7,106

d. 476 : 8,5 = 56