\(\frac{72^2}{24^2}=\frac{3^2.24^2}{24^2}=3^2=9\)

\(\frac{\left(-7,5\right)^2}{2,5^2}=\frac{\left(7,5\right)^2}{\left(2,5\right)^2}=\frac{\left(2,5\right)^2.3^2}{\left(2,5\right)^2}=9\)

\(\frac{15^2}{27}=\frac{3^2.5^2}{27}=\frac{9.25}{27}=\frac{25}{3}\)

\(\frac{72^2}{24^2}=\left(\frac{72}{24}\right)^2=3^2=9\)

\(\frac{\left(-7,5\right)^3}{\left(2,5\right)^3}=\left(\frac{-7,5}{2,5}\right)^3=\left(-3\right)^3=-27\)

\(\frac{15^3}{27}=\frac{15^3}{3^3}=\left(\frac{15}{3}\right)^3=5^3=125\)

Chúc bạn hok tốt 

Silver bullet bn bị sai đề kìa \(\frac{\left(-7,5\right)^3}{\left(2,5\right)^3}\) chứ ko phải \(\frac{\left(-7,5\right)^2}{\left(2,5\right)^2}\)

\(\frac{72^2}{24^2}=\frac{\left(2^3\cdot3^2\right)^2}{\left(2^3\cdot3\right)^2}=\frac{2^6\cdot3^4}{2^6\cdot3^2}=3^2=9\)

\(\frac{15^3}{27}=\frac{3^3\cdot5^3}{3^3}=5^3=125\)

72^2/24^2 = (72/24)^2 = 3^2 = 9

15^3/27 = 15^3/3^3 = (15/3)^3 = 5^3 = 125

\(\frac{72^2}{24^2}=\left(\frac{72}{24}\right)^2=3^2=9\)

\(\frac{15^3}{27^3}=\frac{15^3}{3^3}=\left(\frac{15}{3}\right)^3=5^3=125\)

\(\frac{72^2}{24^2}=\frac{72}{24}=3\)

\(\frac{\left(-7,5\right)^3}{\left(2,5\right)^3}=\frac{-7,5}{2,5}=-3\)

\(\frac{15^3}{27}=\frac{\left(3.5\right)^3}{\left(3.9\right)}=\frac{3^3.5^3}{3.9}=\frac{3^2.5^3}{9}=\frac{9.5^3}{9}=5^3=125\)

a) \(\frac{x}{6}^2=\frac{24}{25}\)

\(\Rightarrow x^2.25=6.24\)

\(\Rightarrow x^2.25=144\)

\(\Rightarrow x^2=144\div25\)

\(\Rightarrow x^2=5,76=2,4^2=\left(-2,4^2\right)\)

\(\Rightarrow x\in\left\{2,4;-2,4\right\}\)

Vậy \(x\in\left\{2,4;-2,4\right\}\)

b) \(\frac{72-x}{7}=\frac{x-40}{9}\)

\(\Rightarrow\left(72-x\right).9=\left(x-40\right).7\)

\(\Rightarrow648-9x=7x-280\)

\(\Rightarrow\left(-280\right)-648\) \(=-9x-7x\)

\(\Rightarrow-928=-16x\)

\(\Rightarrow x=58\)

Vậy \(x=58\)

\(\dfrac{12}{18}=\dfrac{24}{36}=\dfrac{72}{108}=\dfrac{12+24+72}{18+36+108}=\dfrac{12-24+72}{18-36+108}\)

rễ ,chỉ cần gạch thôi

dễ lấy máy tính ra bấm là 618

\(\frac{-3}{24};\frac{-16}{24};\frac{12}{24};\frac{-1}{24};\frac{-20}{24}\)

\(3^{x+2}-3^x=72\)

\(\Rightarrow3^x\cdot\left(3^2-1\right)=72\)

\(\Rightarrow3^x\cdot\left(9-1\right)=72\)

\(\Rightarrow3^x\cdot8=72\)

\(\Rightarrow3^x=\dfrac{72}{8}\)

\(\Rightarrow3^x=9\)

\(\Rightarrow3^x=3^2\)

\(\Rightarrow x=2\)

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