mk đâu thấy hình

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hk tốt

^^

\(\frac{5}{2}+\frac{1}{4}-\frac{1}{2}+\frac{3}{4}-\frac{7}{2}\)

\(=\left(\frac{5}{2}-\frac{1}{2}\right)+\left(\frac{1}{4}+\frac{3}{4}\right)-\frac{7}{2}\)

\(=2+1-\frac{7}{2}\)

\(=3-\frac{7}{2}\)

\(=\frac{6}{2}-\frac{7}{2}\)

\(=\frac{-1}{2}\)

-1/2 nhé bn 

Câu 1 :

( x - 5 )^x = 64 thì có nhiều trường hợp lắm bạn

VD : ( x - 5 )^x = 2^6 = 4^3 = ...

Bạn tự làm nhé

Câu 2 :

\(\left(\frac{3}{2}\right)^x=\frac{81}{16}=\left(\frac{3}{2}\right)^4\)

=> x = 4

\(\frac{3}{5}-\frac{1}{7}+\frac{2}{5}-\frac{6}{7}-\frac{1}{4}\)

\(=\left(\frac{3}{5}+\frac{2}{5}\right)-\left(\frac{1}{7}+\frac{6}{7}\right)-\frac{1}{4}\)

\(=\frac{5}{5}-\frac{7}{7}-\frac{1}{4}\)

\(=1-1-\frac{1}{4}\)

\(=0-\frac{1}{4}\)

\(=-\frac{1}{4}\)

\(\frac{3}{5}-\frac{1}{7}+\frac{2}{5}-\frac{6}{7}-\frac{1}{4}\)

\(=\left(\frac{3}{5}+\frac{2}{5}\right)-\left(\frac{1}{7}+\frac{6}{7}\right)-\frac{1}{4}\)

\(=1-1-\frac{1}{4}\)

\(=-\frac{1}{4}\)

\(-\frac{1}{7}+\frac{5}{3}+\frac{5}{4}+\frac{1}{3}-\frac{3}{2}\)

\(=\left(-\frac{1}{7}+\frac{5}{3}-\frac{3}{2}\right)+\left(\frac{5}{3}+\frac{1}{3}\right)\)

\(=\frac{-6}{42}+\frac{70}{42}-\frac{63}{42}+\frac{6}{3}\)

\(=\frac{-6+70-63}{42}+2\)

\(=\frac{1}{42}+\frac{84}{42}\)

\(=\frac{85}{42}\)

a. Ta có : \(\frac{a}{b}=\frac{c}{d}\Rightarrow ad=bc\)

\(\Rightarrow ac-ad=ac-bc\)

\(\Rightarrow a.\left(c-d\right)=c.\left(a-b\right)\)

\(\Rightarrow\frac{a-b}{a}=\frac{c-d}{c}\)

Câu b,c tương tự