Ta có :

5 = 2  + 3

11 = 5 + 3 . 2

20 = 11 + 3 . 3

32 = 20 + 3 . 4

47 = 32 + 3 . 5

65 = 47 + 3 . 6

Vậy : 2 + 5 + 11 + 20 + 32 + 47 + 56

       = 2 + ( 11 + 32 + 27 ) + 20 + ( 5 + 65 )

       = 2 + 90 + 20 + 70

       = 182

1.\(=56+47-56+53-40\)
\(=\left(56-56\right)+\left(47+53\right)-40\)
\(=0+100-40=60\)
2.\(34+59-34+41+100\)
\(=\left(34-34\right)+\left(59+41\right)+100\)
\(=0+100+100=200\)
3.\(=109+34-109+66-10\)
\(=\left(109-109\right)+\left(34+66\right)-10\)
\(=0+100-10=90\)

1/5

duyệt đi bạn

\(\text{1.-(-66)+34+(-73)-27+99}.\)

\(=66+34-73-27+99=100-100+99=-99.\)

\(\text{2.54-(45-30+54)-30+5}.\)

\(54-45+30-54-30+5=\left(54-54\right)+\left(-45+5\right)+\left(30-30\right)=-40.\)

\(\text{3.42-56+33-(33-56+42)}.\)

\(=42-56+33-33+56-42=\left(42-42\right)+\left(-56+56\right)+\left(33-33\right)=0.\)

\(\text{4.50-(47+50-18)+(47-18)}.\)

\(=50-47-50+18+47-18=\left(50-50\right)+\left(-47+47\right)+\left(18-18\right)=0.\)

\(\text{5.10-(28-30+4)}.\)

\(=10-28+30-4=10+30-20-8-4=20-12=8.\)

\(\text{6.-(-73)+(44-94+27)+94}.\)

\(=73+44-94+27+94=\left(73+27\right)+\left(-94+94\right)+44=100+44=144.\)

1: =66+34-73-27+99=99

2: =54-45+30-54-30+5=-40

3: =42-56+33-33+56-42=0

4: =50-47-50+18+47-18=0

5: =10-28+30-4=2-4+10=12-4=8

1) 195-(2.3\(^3\) - 100 : 5\(^2\))

= 195-(2.27 - 100 : 25)

= 195-(54 - 4)

= 195-50

= 145

2) -47.43 + (-47).56 + (-47)

= -47.43 + (-47).56 + (-47).1

= -47.(43+56+1)

= -47.100

= -4700

1) Ta có: \(195-\left(2\cdot3^3-\frac{100}{5^2}\right)\)

\(=195-\left(54-4\right)=195-50=145\)

2) Ta có: \(-47\cdot43+\left(-47\right)\cdot56+\left(-47\right)\)

\(=-47\left(43+56+1\right)=-47\cdot100=-4700\)

a) x = 6

b) x = 2

c) x = 7

d) x = -1

=2093

-4.3634111e+18

HT

@acquybemon

1; - (-66) + 34 + (-73) - 27 + 99 

=  66 + 34 - 73 - 27 + 99

=  (66 + 34) - (73 + 27) + 99

=  100 - 100 + 99

=  0 + 99

=    99

2; 54 - (45 - 30 + 54) - 30 + 5

= 54 - 45 + 30 - 54 - 30 + 5

= (54 - 54) + (30 - 30) - (45 - 5)

= 0 + 0 - 40

= - 40 

3; 42 - 56 + 33 - (33 + 56 + 42)

= 42 - 56 + 33 - 33 - 56 - 42

= (42 - 42) - (33 - 33) - (56 + 56)

= 0 - 0 - 112

= - 112 

Bài 1: 

1) Ta có: \(\left(-12\right)+6\cdot\left(-3\right)\)

\(=-12-18\)

=-30

2) Ta có: \(\left(36-2020\right)+\left(2019-136\right)-27\)

\(=36-2020+2019-136-27\)

\(=1-100-27\)

\(=-126\)

3) Ta có: \(\left(144-97\right)-\left(244-197\right)\)

\(=144-97-244+197\)

\(=-100+100=0\)

4) Ta có: \(\left(-24\right)\cdot13-24\cdot\left(-3\right)\)

\(=-24\cdot13+24\cdot3\)

\(=24\cdot\left(-13+3\right)\)

\(=24\cdot\left(-10\right)=-240\)

5) Ta có: \(54+55+56+57+58-\left(64+65+66+67+68\right)\)

\(=54+55+56+57+58-64-65-66-67-68\)

\(=\left(54-64\right)+\left(55-65\right)+\left(56-66\right)+\left(57-67\right)+\left(58-68\right)\)

\(=\left(-10\right)+\left(-10\right)+\left(-10\right)+\left(-10\right)+\left(-10\right)\)

=-50

6) Ta có: \(24\cdot\left(16-5\right)-16\cdot\left(24-5\right)\)

\(=24\cdot16-24\cdot5-16\cdot24+16\cdot5\)

\(=-24\cdot5+16\cdot5\)

\(=5\cdot\left(-24+16\right)\)

\(=-5\cdot8=-40\)

7) Ta có: \(47\cdot\left(23+50\right)-23\cdot\left(47+50\right)\)

\(=47\cdot23+47\cdot50-23\cdot47-23\cdot50\)

\(=47\cdot50-23\cdot50\)

\(=50\cdot\left(47-23\right)\)

\(=50\cdot24=1200\)

8) Ta có: \(\left(-31\right)\cdot47+\left(-31\right)\cdot52+\left(-31\right)\)

\(=-31\cdot\left(47+52+1\right)\)

\(=-31\cdot100=-3100\)

Bài 2: 

1) Ta có: \(-17-\left(2x-5\right)=-6\)

\(\Leftrightarrow-17-2x+5+6=0\)

\(\Leftrightarrow-2x-6=0\)

\(\Leftrightarrow-2x=6\)

hay x=-3

Vậy: x=-3

2) Ta có: \(10-2\left(4-3x\right)=-4\)

\(\Leftrightarrow10-8+6x+4=0\)

\(\Leftrightarrow6x+6=0\)

\(\Leftrightarrow6x=-6\)

hay x=-1

Vậy: x=-1

3) Ta có: \(-12+3\left(-x+7\right)=-18\)

\(\Leftrightarrow-12-3x+21+18=0\)

\(\Leftrightarrow-3x+27=0\)

\(\Leftrightarrow-3x=-27\)

hay x=9

Vậy: x=9

4) Ta có: \(-45:\left[5\cdot\left(-3-2x\right)\right]=3\)

\(\Leftrightarrow5\cdot\left(-3-2x\right)=-15\)

\(\Leftrightarrow-2x-3=-3\)

\(\Leftrightarrow-2x=0\)

hay x=0

Vậy: x=0

5) Ta có: x(x+3)=0

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x+3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-3\end{matrix}\right.\)

Vậy: \(x\in\left\{0;-3\right\}\)

6) Ta có: (x-2)(x+4)=0

\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\x+4=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-4\end{matrix}\right.\)

Vậy: \(x\in\left\{2;-4\right\}\)

7) Ta có: \(x\left(x+1\right)\left(x-3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x+1=0\\x-3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\\x=3\end{matrix}\right.\)

Vậy: \(x\in\left\{0;-1;3\right\}\)

Bài 1: 

1) Ta có: (−12)+6⋅(−3)(−12)+6⋅(−3)

=−12−18=−12−18

=-30

2) Ta có: (36−2020)+(2019−136)−27(36−2020)+(2019−136)−27

=36−2020+2019−136−27=36−2020+2019−136−27

=1−100−27=1−100−27

=−126

Tớ chcs cậu học thật giỏi nha !