\(a,\frac{15^3.\left(-5\right)^4}{\left(-3\right)^5.5^6}\)\(=\frac{3^3.5^3}{\left(-3\right)^5.5^2}\)\(=-\frac{5}{\left(3\right)^2}=-\frac{5}{9}\)

\(b,\frac{6^3.2.\left(-3\right)^2}{\left(-2\right)^9.3^7}\)\(=-\frac{6^3}{2^8.3^5}\)\(=-\frac{2^3.3^3}{2^8.3^5}\)\(=-\frac{1}{2^5.3^2}=-\frac{1}{288}\)

\(c,\frac{3^6.7^2-3^7.7}{3^7.21}\)\(=\frac{3^6.7\left(7-3\right)}{3^7.21}\)\(=\frac{3^6.7.4}{3^7.7.3}\)\(=\frac{4}{3.3}=\frac{4}{9}\)

\(a,\left(x-1,2\right)^2=4\)

\(\Rightarrow x-1,2=2\)

\(\Rightarrow x=3,2\)

\(b,\left(x+1\right)^3=-125\)

\(\Rightarrow\left(x+1\right)^3=\left(-5\right)^3\)

\(\Rightarrow x+1=-5\Rightarrow x=-6\)

\(c,\left(x-5\right)^3=2^6\)

\(\Rightarrow\left(x-5\right)^3=4^3\)

\(\Rightarrow x-5=4\Rightarrow x=9\)

\(d,\left(2x+1\right)^{x+1}=5^{x+1}\)

\(\Rightarrow2x+1=5\Rightarrow x=2\)

bn lấy máy tính mà tính ý

Bài1:

Ta có:

a)\(\sqrt{\dfrac{3^2}{5^2}}=\sqrt{\dfrac{9}{25}}=\dfrac{3}{5}\)

b)\(\dfrac{\sqrt{3^2}+\sqrt{42^2}}{\sqrt{5^2}+\sqrt{70^2}}=\dfrac{\sqrt{9}+\sqrt{1764}}{\sqrt{25}+\sqrt{4900}}=\dfrac{3+42}{5+70}=\dfrac{45}{75}=\dfrac{3}{5}\)

c)\(\dfrac{\sqrt{3^2}-\sqrt{8^2}}{\sqrt{5^2}-\sqrt{8^2}}=\dfrac{\sqrt{9}-\sqrt{64}}{\sqrt{25}-\sqrt{64}}=\dfrac{3-8}{5-8}=\dfrac{-5}{-3}=\dfrac{5}{3}\)

Từ đó, suy ra: \(\dfrac{3}{5}=\sqrt{\dfrac{3^2}{5^2}}=\dfrac{\sqrt{3^2}+\sqrt{42^2}}{\sqrt{5^2}+\sqrt{70^2}}\)

Bài 2:

Không có đề bài à bạn?

Bài 3:

a)\(\sqrt{x}-1=4\)

\(\Rightarrow\sqrt{x}=5\)

\(\Rightarrow x=\sqrt{25}\)

\(\Rightarrow x=5\)

b)Vd:\(\sqrt{x^4}=\sqrt{x.x.x.x}=x^2\Rightarrow\sqrt{x^4}=x^2\)

Từ Vd suy ra:\(\sqrt{\left(x-1\right)^4}=16\)

\(\Rightarrow\left(x-1\right)^2=16\)

\(\Rightarrow\left(x-1\right)^2=4^2\)

\(\Rightarrow x-1=4\)

\(\Rightarrow x=5\)

B)ĐỀ BÀI \(\Leftrightarrow\left(\frac{X}{2}\right)^3=\frac{X}{2}.\frac{Y}{3}.\frac{Z}{5}=\frac{810}{30}=27\\ \)

             \(\Leftrightarrow\frac{X}{2}=3\Rightarrow X=6\)

 TỪ ĐÓ SUY RA Y=9;Z=15

A=I x-2 I + I x+5 I>=I x-2-x-5 I=7

Vậy minA=7 <=> -2<= x <= 5

bài 1 a)\(\left(2x-3\right)\left(x^2+0,75\right)=0\)

=>\(\begin{cases}2x-3=0\\ x^2+0,75=0\end{cases}\)

=>\(\begin{cases}2x=3\\ x^2=-0,75\left(vôlý\right)\end{cases}\)

\(\Rightarrow x=3:2\)

\(x=\frac32\)

vậy \(x=\frac32\)

b)\(\frac{x+3}{-2}=\frac{-8}{x+3}\)

=>\(\left(x+3\right)\times\left(x+3\right)=-8\times\left(-2\right)\)

\(\left(x+3\right)^2=16\)

\(x+3=\left(\pm4\right)\)

\(x+3=4\) hoặc \(x+3=-4\)

\(x=4-3\) hoặc \(x=-4-3\)

\(x=1\) hoặc \(x=-7\)

vậy\(x\in\left\lbrace-7;1\right\rbrace\)

nhưng x là số gì

x ϵ z

a, \(\dfrac{5}{6}-\left|2-x\right|=\dfrac{1}{3}\Rightarrow\dfrac{5}{6}-\dfrac{1}{3}=\left|2-x\right|\)

<=> \(\dfrac{1}{2}=\left|2-x\right|\) \(\Leftrightarrow\left[{}\begin{matrix}2-x=\dfrac{1}{2}\\2-x=\dfrac{-1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{5}{2}\end{matrix}\right.\)

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Mấy câu sau tương tự thôi

a)\(\dfrac{3}{2}hay\dfrac{-3}{2}\)

b)\(\dfrac{13}{20}hay\dfrac{-13}{20}\)

c)\(\dfrac{11}{6}hay\dfrac{-11}{6}\)

d)\(\dfrac{4}{3}hay\dfrac{-4}{3}\)

e)\(\dfrac{1}{5}hay\dfrac{-1}{5}\)

Đây là câu trả lời của mình

Hay có nghĩa là hoặc

\(\left(x-\frac{7}{3}\right):2\frac{3}{21}+\frac{3}{5}=0,16\)

<=> \(\left(x-\frac{7}{3}\right):\frac{45}{21}+\frac{3}{5}=\frac{4}{25}\)

<=> \(\left(x-\frac{7}{3}\right):\frac{15}{7}=-\frac{11}{25}\)

<=> \(x-\frac{7}{3}=\frac{-33}{35}\)

<=> \(x=\frac{146}{105}\)

\(\left(x+\frac{5}{6}\right).2\frac{2}{5}-1\frac{1}{4}=0,35\)

<=> \(\left(x+\frac{5}{6}\right).\frac{12}{5}-\frac{5}{4}=\frac{7}{20}\)

<=> \(\left(x+\frac{5}{6}\right).\frac{12}{7}=\frac{8}{5}\)

<=> \(x+\frac{5}{6}=\frac{14}{15}\)

<=> \(x=\frac{1}{10}\)

học tốt