\(=\left(189-\left(34+15\right)\right)\div20=\left(189-49\right)\div20=140\div20=7\)

=(189 - ( 34 + 15 ) ) : 20 = ( 189 - 49 ) : 20 = 140 : 20 =7 

k nha bạn

\(\left\{189-\left[34+\left(20-5\right)\right]\right\}\div20\)

\(=\left\{189-\left[34+15\right]\right\}\div20\)

\(=\left\{189-49\right\}\div20\)

\(=140\div20\)

\(=7\)

a, (-115)+(-40)+115+|-35|

=[(-115) +115] + [(-40) +35]

=-5

b)[ 189 - (34+20-5)] : 20

= (189-49) :20

= 140:20 =7

2.a) x-15= 20.2²

<=> x-15 = 80

<=> x=80 + 15

<=> x=95

VẬy x=95

b) 48 +5(x-3) = 63

<=> 5(x-3) = 63-48

<=> 5(x-3) =15

<=> x-3 = 15:5

<=>x-3 = 3

<=> x=6

Vậy x=6

c) |x| -2 = 7-(-8)

<=> |x| -2 = 15

<=> |x| =15+2

<=> |x| = 17

<=>\(\left[{}\begin{matrix}x=17\\x=-17\end{matrix}\right.\)

Vậy x=17 hoặc x=-17

bai 1

20:(24-(3^2.4-34)^2)-20

=20:(24-(9.4-34)^2)-20

=20:(24-2^2)-20

=20:20-20

=-19

bai 2

a

14+5x=4^6:4^3

14+5x=4^3

14+5x=64

5x=64-14

5x=50

x=50:5

x=10

b

189-2.(93-x)=59

2..(93-x)=189-59

2.(93-x)=130

(93-x)=130:2

93-x=65

x=93-65

x=28

1) \(20:\left[24-\left(3^2.4-34\right)^2\right]-20\)

\(=20:\left[24-\left(9.4-34\right)^2\right]-20\)

\(=20:\left[24-4\right]-20\)

\(=20:20-20\)

\(=1-20\)

\(=-19\)

2)a.\(14+5x=4^6:4^3\)

       \(14+5x=64\)

       \(5x=64-14\)

       \(5x=50\)

    \(\Rightarrow x=10\)

b)     189-2(93-x)=59

         2(93-x)       =189-59

        2(93-x)        =130

           93-x          =130:2

           93-x          =65

               x            =93-65

               x            =28

Học tốt nha!!!

a) 5²⁰<3³⁰<3³⁴

5²⁰=(5²)¹⁰=25¹⁰

3³⁰=(3³)¹⁰=27¹⁰

vi 25¹⁰ <27¹⁰ nen 5²⁰ <3³⁰ va3³⁰<3³⁴

=> 5²⁰<3³⁴

^b) 71⁵<72⁵<16²⁰<17²⁰

72⁵ = (8.9)⁵=8⁵.9⁵=8⁵. 3¹⁰

16²⁰=(8.2)²⁰=8²⁰.2²⁰=8²⁰.4¹⁰

vi 8⁵ <8²⁰ va 3¹⁰<4¹⁰

nen 72⁵<16²⁰

-> 71⁵<17²⁰

Vi sao biet 5^20 >3^30

1) \(\left(+15\right)+\left(+17\right)=15+17=32\)

2) \(\left(-3\right)+\left(-7\right)=-3-7=-\left(3+7\right)=-10\)

3) \(\left(-25\right)+\left(+4\right)=-25+4=-\left(25-4\right)=-21\)

4) \(\left(-6\right)+\left(-54\right)=-6-54=-\left(6+54\right)=-60\)

5) \(\left(-15\right)+20=20-15=5\)

6) \(\left(-5\right)+8+7+5\)

\(=\left(-5+5\right)+\left(8+7\right)\)

\(=15\)

7) \(\left(-8\right)+\left(-11\right)+\left(-2\right)\)

\(=\left[\left(-8\right)+\left(-2\right)\right]+\left(-11\right)\)

\(=\left(-10\right)+\left(-11\right)\)

\(=-21\)

8) \(15+\left(-5\right)+\left(-14\right)+\left(-16\right)\)

\(=\left[15+\left(-5\right)\right]+\left[\left(-14\right)+\left(-16\right)\right]\)

\(=10+\left(-30\right)\)

\(=-20\)

9) \(\left(-20\right)+\left(-14\right)+3+\left(-86\right)\)

\(=\left[\left(-20\right)+3\right]+\left[\left(-14\right)+\left(-86\right)\right]\)

\(=\left(-17\right)+\left(-100\right)\)

\(=-117\)

10) \(\left(-136\right)+123+\left(-264\right)+\left(-83\right)+240\)

\(=\left[\left(-136\right)+\left(-264\right)\right]+\left[123+\left(-83\right)\right]+240\)

\(=\left(-400\right)+40+240\)

\(=\left(-360\right)+240\)

\(=-120\)

11) \(\left(-596\right)+2001+1999+\left(-404+189\right)\)

\(=\left(-596\right)+2001+1999-404+189\)

\(=\left[\left(-596\right)-404\right]+\left(2001+189\right)+1999\)

\(=\left(-1000\right)+2190+1999\)

\(=1190+1999\)

\(=3189\)

12) \(314+\left(-153\right)+64+121+\left(-247\right)+218\)

\(=\left(314+64+121\right)+\left[\left(-153\right)+\left(-247\right)\right]+218\)

\(=\left(378+121\right)+\left(-400\right)+218\)

\(=499-400+218\)

\(=99+218\)

\(=317\)

\(\text{#}Toru\)

đổi ra j

=500yen+200yen+34yen=734yen

25 x 35 x 2 x 40 x 50= ?

b/ Ta có: 17²⁰ = (17⁴)⁵ = 83521⁵

Vì 71⁵ < 83521⁵ nên 71⁵ < 17²⁰.