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\(\frac{45^{10}\times5^{20}}{75^{15}}=\frac{3^{20}\times5^{10}\times5^{20}}{3^{15}\times5^{30}}=3^5=243\)
\(\frac{45^{10}\times5^{20}}{75^{15}}=243\)
mk ko nhớ cách giải, chỉ có kết quả, nếu đúng k cho mk nha
\(\frac{45^{10}.5^{20}}{75^{15}}\)
\(=\frac{\left(15.3\right)^{10}.5^{20}}{\left(15.5\right)^{15}}\)
\(=\frac{15^{10}.3^{10}.5^{20}}{15^{15}.5^{15}}\)
\(=\frac{3^{10}.5^5}{15^5}=\frac{3^{10}.5^5}{3^5.5^5}=3^5=243\)
\(\frac{45^{10}.5^{20}}{75^{15}}=\frac{\left(9.5\right)^{10}.5^{20}}{\left(3.5.5\right)^{15}}=\frac{9^{10}.5^{10}.5^{20}}{3^{15}.5^{15}.5^{15}}=\frac{9^{10}.5^{30}}{3^{15}.5^{30}}=\frac{9^{10}}{3^{15}}=243\)
Bài 1:
a)
\(\frac{8^{20}+4^{20}}{4^{25}+64^5}=\frac{(2^3)^{20}+(2^2)^{20}}{(2^2)^{25}+(2^6)^{5}}=\frac{2^{60}+2^{40}}{2^{50}+2^{30}}=\frac{2^{40}(2^{20}+1)}{2^{30}(2^{20}+1)}=2^{10}\)
b)
\(\frac{45^{10}.5^{20}}{75^{15}}=\frac{(3^2.5)^{10}.5^{20}}{(3.5^2)^{15}}=\frac{3^{20}5^{30}}{3^{15}.5^{30}}=\frac{3^{20}}{3^{15}}=3^5\)
Bài 2:
Ta thấy $(x-2)^{2012}=[(x-2)^{1006}]^2\geq 0$ với mọi $x\in\mathbb{R}$
$|b^2-9|^{2014|\geq 0$ với mọi $b\in\mathbb{R}$ (tính chất trị tuyệt đối)
Do đó để tổng của chúng bằng $0$ thì:
\((x-2)^{2012}=|b^2-9|^{2014}=0\)
\(\Leftrightarrow \left\{\begin{matrix} x-2=0\\ b^2-9=0\end{matrix}\right.\Leftrightarrow \left\{\begin{matrix} x=2\\ b=\pm 3\end{matrix}\right.\)
Vậy.......
\(75^{20}=45^{10}.5^{30}\)
\(45^{10}.5^{30}\)
=\(\left(3^2.5\right)^{10}.5^{10+20}\)
= \(\left(3^2\right)^{10}.5^{10}.5^{30}\)
= \(3^{20}.5^{40}\)
= \(3^{20}.\left(5^2\right)^{20}\)
= \(3^{20}.25^{20}\)
= \(75^{20}\)
Câu 4:
a: Xét ΔABD và ΔAED có
AB=AE
\(\widehat{BAD}=\widehat{EAD}\)
AD chung
Do đó: ΔABD=ΔAED
Câu 1:
\(a,=\dfrac{1}{2}+9\cdot\dfrac{1}{9}-18=\dfrac{1}{2}+1-18=-\dfrac{33}{2}\\ b,=2-1+4\cdot\dfrac{1}{4}+9\cdot\dfrac{1}{9}\cdot9=1+1+9=11\\ c,=-21,3\left(54,6+45,4\right)=-21,3\cdot100=-2130\\ d,B=\left(\dfrac{1}{16}+\dfrac{1}{2}-\dfrac{1}{16}\right):\left(\dfrac{1}{8}-\dfrac{1}{8}+1\right)=\dfrac{1}{2}:1=\dfrac{1}{2}\)
\(\frac{45^{10}.5^{20}}{75^5}\)
\(=\frac{\left(3^2.5\right)^{10}.5^{20}}{\left(5^2.3\right)^5}\)
\(=\frac{3^{20}.5^{10}.5^{20}}{5^{10}.3^5}\)
\(=3^{15}.5^{20}\)
\(\frac{45^{10}.5^{20}}{75^5}=\frac{9^{10}.5^{10}.5^{20}}{25^5.3^5}=\frac{3^{20}.5^{10}.5^{20}}{5^{10}.3^5}=\frac{3^{20}.5^{30}}{5^{10}.3^5}=3^{15}.5^{20}\)