1)

\(\frac{7.8^3-5.2^{10}}{\left(-16\right)^2}\)       

=  \(\frac{7.2^8.2-5.2^8.2^2}{16^2}\)

=  \(\frac{2^8.\left(2.7-5.2^2\right)}{2^8}\)

=   \(\frac{2^8.\left(-6\right)}{2^8}\)

=   \(-6\)

2)

b)\(\frac{-28}{4}\le x\le\frac{-21}{7}\)

\(\Rightarrow-7\le x\le-3\)

\(\Rightarrow x=\left\{-7;-6;-5;-4;-3\right\}\)

2)

a)\(\frac{108}{12}\le x\le\frac{91}{7}\)

\(\Rightarrow9\le x\le13\)

\(\Rightarrow x=\left\{9;10;11;12;13\right\}\)

\(\frac{-32}{4}\le x\le\frac{-28}{7}\)

\(-8\le x\le-4\)

\(\Rightarrow x=-4;-5;-6;-7;-8\)

\(\text{Vậy }A=\left\{-4;-5;-6;-7;-8\right\}\)

-6;-5;-4

\(\frac{-28}{4}\le x< \frac{-21}{7}=-7\le x< -3=\left\{-7;-6;-5;-4\right\}\)

Ta có :

\(\frac{-144}{12}\)\(=-12\)

\(\frac{-40}{5}\)\(=-8\)

\(\Rightarrow-12\le x\le-8\)

x thuộc { -12 ; -11 ; -10 ; -9 ; -8 }

Vậy A = { -12 ; -11 ; -10 ; -9 ; -8 }

A={-12;-11;-10;-9;-8}

Ta có : 

\(\frac{-144}{12}=-12\)

\(\frac{-40}{5}=-8\)

\(\Rightarrow-12\le x\le-8\)

\(\Rightarrow x\in\) { -12 ; -11 ; -10 ; -9 ; -8 }

ta có -25/4=-175/28   

          21/7=84/28

=>25/7< -174/28< -173/28<....<83/24<82428

=> ... là -174/28<173/28...<83/28

gọi số cần tìm là x=y/13

để x ngyên =>13 thuộc ư(y)

=>y ={-13;13;26;-26;39;-39...}

vì -34/13 < y/31

=> y={-13;-26}

mà x nhỏ nhất => y nhỏ nhất

=>y =26

=> phân số cần tìm là -26/13=-2

\(a.\frac{2}{x}=\frac{x}{8}\)

\(\Rightarrow x^2=2.8\)

\(\Rightarrow x^2=16\)

\(\Rightarrow x^2=4^2\)

\(\Rightarrow x=4\)

\(b.\frac{-28}{4}\le x\le\frac{-21}{7}\)

\(\Rightarrow\frac{-196}{28}\le\frac{28x}{28}\le\frac{-84}{28}\)

\(\Rightarrow-196\le28x\le-84\)

Mà \(28x⋮28\)

\(\Rightarrow28x\in\left\{-84;-112;-140;-168;-196\right\}\)

\(\Rightarrow x\in\left\{-3;-4;-5;-6;-7\right\}\)

a, =>x.x=2.8

=>x²=16=4²=-4²=2⁴=-2⁴

1,x=4 ; 2,x=-4 ; 3,x=2 ; 4,x=-2

b, =>-7 \<x\<-3

=>x=-6;-5;-4

dấu \< thay cho dấu nhỏ hơn hoặc bằng nha bạn !!!!!!!!!
 

Bài làm:

Ta có: \(-\frac{7}{12}\le x\le\frac{1}{4}\)

\(\Leftrightarrow-1< x< 1\)

\(\Rightarrow x=0\)

Vậy x = 0 

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Ta có: \(\frac{1}{4}=\frac{3}{12}\)

\(=>\frac{-7}{12}\le x\le\frac{3}{12}\)

\(=>x=\frac{-7}{12};\frac{-6}{12};\frac{-5}{12};\frac{-4}{12};\frac{-3}{12};\frac{-2}{12};\frac{-1}{12};\frac{1}{12};\frac{2}{12};\frac{3}{12}\)

\(\Leftrightarrow\dfrac{46}{7}+\dfrac{81}{35}< =x< =\dfrac{49}{36}\)

\(\Leftrightarrow\dfrac{311}{35}< =x< =\dfrac{49}{36}\)

\(\Leftrightarrow x\in\varnothing\)