\(A=\frac{34}{7.13}+\frac{51}{13.22}+\frac{85}{22.37}+\frac{68}{37.49}\)

\(=\frac{17.2}{7.13}+\frac{17.3}{13.22}+\frac{17.5}{22.37}+\frac{17.4}{37.49}\)

\(=17\left(\frac{2}{7.13}+\frac{3}{13.22}+\frac{5}{22.37}+\frac{4}{37.49}\right)\)

\(=\frac{17}{3}\left(\frac{6}{7.13}+\frac{9}{13.22}+\frac{15}{22.37}+\frac{12}{37.49}\right)\)

\(=\frac{17}{3}\left(\frac{1}{7}-\frac{1}{13}+\frac{1}{13}-\frac{1}{22}+...+\frac{1}{37}-\frac{1}{49}\right)\)

\(=\frac{17}{3}\left(\frac{1}{7}-\frac{1}{49}\right)\)\(=\frac{17}{3}.\frac{6}{49}=\frac{17.2}{49}=\frac{34}{49}\)

Có : \(\frac{17}{24}=\frac{34}{48}\)

Vì 48 < 49 => \(\frac{34}{48}>\frac{34}{49}\). Hay \(\frac{17}{24}>A\)

cảm ơn Văn B ? nha !

a) 49 - 9 . [ 3⁴ : 3¹ - ( 12 - 4 ) : 2²  ]

= 49 - 9 . [ 3³ - 8 : 2² ]

=  49 - 9 . [ 3³ -2³ : 2² ]

=  49 - 9 . [ 3³ - 2 ]

= 49 - 9 . [ 27 - 2 ]

= 49 - 9 . 25

= 49 - 225 = -176

b) 4.5² + 16 : 2²

= 4. 25 + 2⁴ : 2²

= 100 + 2² = 100+ 4 =104

--tho--là tớ💋

c) 5³ : 5 - 2017⁰

= 5² - 1 = 25 - 1= 24 

d) 2² . 3 - ( 10⁰ + 8 ) : 3²

= 4. 3 - ( 1 + 8 ) : 3²

= 4. 3 - 9 : 3²

= 12 - 3² : 3²

= 12 - 1 = 11.

--tho--là tớ💋

khổ qua

4, 7, 9 là ước của a

4;7;9;21

a ) x = 5 4 x = − 5 4 b ) x = 3 2 x = − 1 2 c ) x = 3 2 x = − 1 2

d ) x = 59 40 x = 61 40 e ) x = 1 3 x = − 1 f ) x = 1 3 x = − 1

\(a)196:4-12.\left(-5\right)=49+60=109.\\ b)2^2.5+\left(49-17^2\right)=4.5+49-289=20-240=-220.\\ c)29.\left(15-34\right)-15.\left(29-34\right)=29.15-29.34-15.29+15.34=-29.34+15.34=-476.\)

Bài 2: 

Gọi số sách là x

Theo đề, ta có: \(x\in BC\left(10;12;15\right)\)

mà 100<=x<=150

nên x=120

Đáp án D

34 x 52 - 34 + 34 x 49 

= 34 x 52 - 34 x 1+ 34 x 49 

= 34 x ( 52 - 1 + 49 )

= 34 x 100

= 3400

sao nhieu qua zay