ai giup minh khong nhi

1090

3186

19991

200

3642

500

1000

800

1999

8560

999 x 46587 x 452  = 21036266676

1. -452-(-67+75-452)

= -452+67-75+452

= (-452+452)+(67-75)

= 0+(-8)

= -8

2. (55+45+15)-(15-55+45)

= 55+45+15-15+55-45

= (55+55)+(45-45)+(15-15)

= 110+0+0

= 110

1) 3x = 45 + 15 = 60

x = 60 : 3 = 20

2) 5x = 50 - 35 = 15

x = 15 : 5 = 3

3) (2x - 5) + 17 = 6

2x - 5 = 6 - 17

2x - 5 = -11

2x = -11 + 5

2x = -6

x = -6 : 2 = -3

4) 10 - 2(4 -3x) = -4

2(4 - 3x) = -4 - 10 = -14

4 - 3x = -14 : 2 = -7

3x = -7 - 4 = -18

x = -18 : 3 = -6

\(\left\{{}\begin{matrix}\left\{{}\begin{matrix}3x-15=45\Leftrightarrow3x=60\Leftrightarrow x=20\\35-5x=50\Leftrightarrow5x=-15\Leftrightarrow x=-3\end{matrix}\right.\\\left\{{}\begin{matrix}\left(2x-5\right)+17=6\Leftrightarrow2x+5=-11\Leftrightarrow2x=-16\Leftrightarrow x=-8\\10-2\left(4-3x\right)=-4\Leftrightarrow8-6x=14\Leftrightarrow6x=-6\Leftrightarrow x=-1\end{matrix}\right.\\\left\{{}\begin{matrix}-12+3\left(-x+7\right)=-18\Leftrightarrow-3x+21=-6\Leftrightarrow-3x=-27\Leftrightarrow x=9\\24:\left(3x-2\right)=-3\Leftrightarrow3x-2=-8\Leftrightarrow3x=-6\Leftrightarrow x=-2\end{matrix}\right.\\-45:5\left(-3-2x\right)=3\Leftrightarrow-15-10x=-15\Leftrightarrow10x=0\Leftrightarrow x=0\end{matrix}\right.\)

SỬA:

\(\left(2x-5\right)+17=6\Leftrightarrow2x-5=-11\Leftrightarrow2x=-6\Leftrightarrow x=-3\)

a) 2³ . 17 - 2³ . 14

= 2³(17-14)

=2³. 3= 24

b) 80 - ( 4 . 5 - 3 . 2³ )

= 80- 2². (5-3.2)= 80- 2².(-1)

= 80- 4.(-1)= 80- (-4)= 84

c) 35 - { 12 - [ -14 + ( -2) }

= 35 - { 12 - (-16) }

=35- 28= 7

d) 49 - ( -45) - 23

= 94-23= 71

e) 13 - 18 - ( -42) - 15

= -5 -(-42) -15

= -20+42= 22

g) -452 - ( -67 + 75 - 452 )

= -452- (8-452)

= -452 -(- 444)= -8

h) |31−17|−|13−52|

= 14- 39= -25

80 -(4.5² -3.2³)

= 80- (4.25- 3.8)

= 80- (100-24)

= 80-76= 4

Mấy bài này bạn vận dụng qui tắc đổi dấu trong ngoặc và bấm máy tính bờ làm thôi

a,\(\left(57-725\right)-\left(605-53\right)\)

\(=57-725-605+53\)

\(=-1220\)

b,\(-452-\left(-67+75-452\right)\)

\(=-452+67-75+452\)

\(=-8\)

c,\(\left(55+45+15\right)-\left(15-55+45\right)\)

\(=55+45+15-15+55-45\)

\(=110\)

TÍnh nhanh

a) 32 - 13 - 17

=  32 - (13 + 17)

= 32 - 30

= 2

b) 45 - 12 - 5 - 23

= (45 - 5) - (12 + 23)

= 40 - 35

= 5

c) 1732 - 513 - 732

= (1732 - 732) - 513

= 1000 - 513

= 487

d) 2834 - 150 - 834

= (2834 - 834) - 150

= 2000 - 150

= 1850

a) 32 - 13 - 17

= 32 - (13 + 17)

= 32 - 30

= 2

b) 45 - 12 - 5 - 23

= 45 - (12 + 5 + 23)

= 45 - 40

= 5

c) 1732 - 513 - 732

= (1732 - 732) - 513

= 1000 - 513

= 487

d) 2834 - 150 - 834

= (2834 - 834) - 150

= 2000 - 150

= 1850