a, 2¹.5².17 = 2.25.17 = 50.17 = 850 

b, 2² + 2³ + 2⁴ = 4 + 8 + 16 = 28

c, 2⁵.3 + 2⁴:8 + 50: 5²

= 32.3 + 16:8 + 50:25

=96 + 2 + 2

= 100

d, 11² - 10² - 3²

= 121 - 100 - 9

= 21 - 9

= 12

e, 1³ + 2³ + 3³ + 4³ + 5³

= ( 1+ 2+3+4+5)²

= 15²

= 225

Lời giải:

$3x-2y+6xy=1$
$\Rightarrow (3x+6xy)-(2y+1)=0$

$\Rightarrow 3x(1+2y)-(2y+1)=0$

$\Rightarrow (1+2y)(3x-1)=0$
$\Rightarrow 1+2y=0$ hoặc $3x-1=0$

$\Rightarrow y=\frac{-1}{2}$ hoặc $x=\frac{-1}{3}$ (vô lý vì $x,y$ là số nguyên)

Vậy không tồn tại $x,y$ thỏa mãn đề.

\(x\) +  \(\dfrac{1}{4}\) + \(x\) + \(\dfrac{3}{2}\) = \(x\) + \(\dfrac{2}{3}\) + \(x\) + 4

\(x\) + \(x\) - \(x\) - \(x\)      = \(\dfrac{2}{3}\) + 4 - \(\dfrac{3}{2}\) - \(\dfrac{1}{4}\)

                      0 = \(\dfrac{35}{12}\) (vô lý)

vậy \(x\) \(\in\) \(\varnothing\)

Dạ cảm ơn cô

Lời giải:
Tổng chiều dài và chiều rộng là: 

$208:2=104$ (cm) 

Chiều dài: $(104+11):2=57,5$ (cm) 

Chiều rộng là: $(104-11):2=46,5$ (cm) 

Chiều cao: $104:2=52$ (cm)

Diện tích xung quanh: 

$208\times 52=10816$ (cm²)

Diện tích toàn phần: $10816+2\times 57,5\times 46,5=16163,5$ (cm²)

a, -(-12) + (+19) - (+12) + 8 - 19

= 12 + 19 - 12 + 8 - 19

= ( 12 - 12) + ( 19- 19) + 8

= 0 + 0 + 8

=  8

b, (59 - 78) - (42 - 78 + 59)

= 59 - 78 - 42 + 78 - 59

= (59 - 59) - 42 - ( 78 - 78)

= 0  - 42 - 0

 = -42

c, ( - 68 + 103) - (-50 - 68 + 103)

= -68 + 103 + 50 + 68 - 103

= (-68 + 68) + ( 103 - 103) + 50

= 0 + 0 + 50

= 50 

a) \(...=12+19-12+8-19=8\)

b) \(...=-19-23=-42\)

c) \(...=35-\left(-15\right)=35+15=50\)

a) \(B\left(16\right)=\left\{0;16;32;48;64;80;96\right\}\)

b) \(U\left(135\right)=\left\{1;3;5;9;15;27;45\right\}\)

c) \(B\left(17\right)=\left\{0;17;34;51;68;85\right\}\)

d) \(U\left(75\right)=\left\{1;3;5;15;25;75\right\}\)

e) \(B\left(33\right)=\left\{0;33;66\right\}\)

f) \(U\left(42\right)=\left\{1;2;3;6;7;14;21;42\right\}\)

Đề bài là gì vậy bạn>

\(a\times100\) + 50 + \(c\) = \(\overline{a5c}\)

\(a\times100\) +  \(b\times10\) + 6 = \(\overline{ab6}\)

\(745-x=304\)

          \(x=745-304\)

          \(x=441\)

\(...\Rightarrow x+x+\dfrac{x}{43}+\dfrac{x}{8}=14+148+\dfrac{10}{30}+\dfrac{5}{95}\)

\(\Rightarrow\left(1+1+\dfrac{1}{43}+\dfrac{1}{8}\right)x=162+\dfrac{1}{3}+\dfrac{1}{19}\)

\(\Rightarrow\left(\dfrac{2.43.8}{43.8}+\dfrac{1.8}{43.8}+\dfrac{1.43}{43.8}\right)x=\dfrac{162.3.19}{3.19}+\dfrac{1.19}{3.19}+\dfrac{1.3}{19.3}\)

\(\Rightarrow\left(\dfrac{688}{344}+\dfrac{8}{344}+\dfrac{43}{344}\right)x=\dfrac{9234}{57}+\dfrac{19}{57}+\dfrac{3}{57}\)

\(\Rightarrow\dfrac{739}{344}x=\dfrac{9256}{57}\)

\(\Rightarrow x=\dfrac{9256}{57}:\dfrac{739}{344}=\dfrac{9256}{57}.\dfrac{344}{739}=\dfrac{\text{3184064}}{\text{42123}}\)

\(x\) + \(\dfrac{1}{10}\) + \(x\) + \(\dfrac{1}{11}\) = \(x\) + \(\dfrac{1}{21}\)

\(x+x-x\) = \(\dfrac{1}{21}\) - \(\dfrac{1}{10}\) - \(\dfrac{1}{11}\)

\(x\)             = -  \(\dfrac{331}{2310}\)

\(x+\dfrac{1}{10}+x+\dfrac{1}{11}=x+\dfrac{1}{21}\)

\(x+x-x=\dfrac{1}{21}-\dfrac{1}{10}-\dfrac{1}{11}\)

\(x=\dfrac{-11}{210}-\dfrac{1}{11}\)

\(x=\dfrac{-331}{2310}\)