I don't now

mik ko biết 

sorry 

......................

a. 4² x 102 - 4³ x 17 - 4² x 34

= 4² x (102 - 4 x 17 -34)

= 4² x 0

= 0

b. 7³ x 9 + 3² x 7⁴ - 45 x 539

= 3087 + 21609 - 24255

= 24696 - 24255

= 441

\(4^2.120-4^3:17+4^2.34\)

\(=4^2.120-4^3.\frac{1}{7}+4^2.34\)

\(=4^2.\left(120-\frac{4}{17}+34\right)\)

\(=4^2.\frac{2614}{17}\)

\(=\frac{41824}{17}\)

CẬU GHI SAI MỘT BƯỚC 

Kết quả đúng rồi đó                              

Lời giải:

\(4^2.120-4^3.17+4^2-3^4\)

\(=4^2(120-4.17+1)-3^4=4^2.53-3^4\)

\(=848-81=767\)

đây bạn

chịu

Chịu 

a)  1376

b) 441

a: \(\frac{52}{17}>\frac{51}{17}=3\)

\(3=\frac{121}{41}>\frac{120}{41}\)

Do đó: \(\frac{52}{17}>\frac{120}{41}\)

b: \(\frac34+\frac14:\left(\frac{7}{12}-\frac16\right)\)

\(=\frac34+\frac14:\left(\frac{7}{12}-\frac{2}{12}\right)\)

\(=\frac34+\frac14:\frac{5}{12}\)

\(=\frac34+\frac14\times\frac{12}{5}=\frac34+\frac35=\frac{15}{20}+\frac{12}{20}=\frac{27}{20}\)

c: \(372,463\cdot998+744,926\)

\(=372,463\cdot998+372,463\cdot2\)

\(=372,463\times\left(998+2\right)=372,463\times1000=372463\)

d: Số số hạng trong dãy số 2;4;6;...;100 là:

\(\left(100-2\right):2+1=98:2+1=49+1=50\) (số)

\(2-4+6-8+10-12+\cdots+98-100+102\)

\(=\left(2-4\right)+\left(6-8\right)+\cdots+\left(98-100\right)+102\)

=(-2)+(-2)+...+(-2)+102

\(=-2\cdot\frac{50}{2}+102=-50+102=52\)

e: (y+112)-113=79

=>y+112-113=79

=>y-1=79

=>y=79+1=80

f: \(\frac34-y=\frac12\)

=>\(y=\frac34-\frac12=\frac14\)

g: \(\left(\frac45-2\times y\right)+\frac16=\frac56\)

=>\(\frac45-2\times y=\frac56-\frac16=\frac46=\frac23\)

=>\(2\times y=\frac45-\frac23=\frac{12}{15}-\frac{10}{15}=\frac{2}{15}\)

=>\(y=\frac{2}{15}:2=\frac{1}{15}\)

h: (y+1)+(y+2)+...+(y+50)=1750

=>50y+(1+2+...+50)=1750

=>\(50y+50\times\frac{51}{2}=1750\)

=>50y+1275=1750

=>50y=1750-1275=475

=>\(y=\frac{475}{50}=9,5\)