\(\frac{10-3n}{5-3n}\inℤ\Leftrightarrow\frac{10-n}{5-n}\inℤ\)

\(\Rightarrow\frac{5-n}{n}\inℤ\Leftrightarrow n\in\left\{1;-1;5;-5\right\}\)

Answer:

\(M=\frac{10n-3}{5n-3}=2+\frac{3}{5n-3}\)

Để cho \(M\inℤ\Leftrightarrow2+\frac{3}{5n-3}\inℤ\Rightarrow\frac{3}{5n-3}\inℤ\Rightarrow3⋮5n-3\)

\(\Rightarrow5n-3\inƯ\left(3\right)=\left\{\pm1;\pm3\right\}\)

\(\Rightarrow5n\in\left\{4;2;0;6\right\}\)

\(\Rightarrow n\in\left\{\frac{4}{5};\frac{2}{5};0;\frac{6}{5}\right\}\)

\(\Rightarrow n=0\)

235+ 242,13= 477,13

\(-2\frac{7}{15}=\frac{-2\cdot15+7}{15}=\frac{-23}{15}\)

Vậy hỗn số \(-2\frac{7}{15}\)viết dưới dạng phần số là \(\frac{-23}{15}\)

\(-2\frac{7}{5}=\frac{-2.15+7}{15}=\frac{-23}{15}\)

Vậy hỗn số \(-2\frac{7}{15}\) viết dưới dạng phân số là : \(\frac{-23}{15}\)

a/\(A=\left(3+5\right)^2=8^2=64\)

\(B=3^2+5^2=9+25=34\)

\(\Rightarrow A>B\)

b/ \(C=\left(3+5\right)^3=8^3=512\)

\(D=3^3+5^3=27+125=152\)

\(\Rightarrow C>D\)

a/ A= (3+5)² = 8² = 64

   B = 3² + 5² = 9 + 25 = 34

vì 64>34 => A > B

b/ C = (3+5)³ = 8³ = 512

    D = 3³ + 5³ = 27 + 125 = 152

Vì 512>152 => C > D

320km

3200 hm = 320 km

\(x^2-5x=-1\Leftrightarrow x^2-5x-\left(-1\right)=0\)

\(\Rightarrow x=\frac{-\left(-5\right)\pm\sqrt{\left(-5\right)^2-4\cdot1\cdot1}}{2\cdot1}\)

\(\Leftrightarrow x=\frac{5\pm\sqrt{25-4\cdot1\cdot1}}{2\cdot1}\)

\(\Leftrightarrow x=\frac{5\pm\sqrt{21}}{2}\)

a/ A = 8²

A = 64

B = 9 + 25, B = 34

b/ C = 8³, CC = 512

D = 27 + 125

D = 152

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