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9a.
Do \(P\left(-2\right)=7\)
\(\Rightarrow a.\left(-2\right)+5=7\)
\(\Rightarrow-2a=2\)
\(\Rightarrow a=-1\)
b.
Do \(P\left(0\right)=-2\)
\(\Rightarrow a.0+b=-2\)
\(\Rightarrow b=-2\)
Do \(P\left(-3\right)=-1\)
\(\Rightarrow a.\left(-3\right)+b=-1\)
\(\Rightarrow-3a-2=-1\)
\(\Rightarrow-3a=1\)
\(\Rightarrow a=-\dfrac{1}{3}\)
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Lời giải:
$(-3)^5 = -243$
$(\frac{-1}{3})^5=\frac{(-1)^5}{3^5}=\frac{-1}{243}$
$(0,1)^3=0,001$
$10^3=1000$
$(\frac{2}{5})^2=\frac{2^2}{5^2}=\frac{4}{25}=0,16$
$(-1)^{200}=1$
$\frac{5^6.6^6}{30^4}=\frac{(5.6)^6}{30^4}=\frac{30^6}{30^4}=30^2=900$
$\frac{3^2.12^2}{6^4}=\frac{3^2.2^2.6^2}{6^4}=\frac{(3.2)^2.6^2}{6^4}$
$=\frac{6^2.6^2}{6^4}=\frac{6^4}{6^4}=1$
$\frac{2^{15}.9^4}{6^6.8^3}=\frac{2^{15}.(3^2)^4}{2^6.3^6.(2^3)^3}$
$=\frac{2^{15}.3^{8}}{2^6.3^6.2^9}=\frac{2^{15}.3^8}{2^{15}.3^6}=\frac{3^8}{3^6}=3^2=9$
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\(\dfrac{9^{15}.8^{11}}{3^{29}.16^8}=\dfrac{\left(3^2\right)^{15}.\left(2^3\right)^{11}}{3^{29}.\left(2^4\right)^8}=\dfrac{3^{30}.2^{33}}{3^{29}.2^{32}}\)
Ta lấy vễ trên chia vế dưới
\(=3.2=6\)
\(\dfrac{2^{11}.9^3}{3^5.16^2}=\dfrac{2^{11}.\left(3^2\right)^3}{3^5.\left(2^4\right)^2}=\dfrac{2^{11}.3^6}{3^5.2^8}\)
Ta lấy vế trên chia vế dưới
\(=2^3.3=24\)
\(\dfrac{9^{15}.8^{11}}{3^{29}.16^8}=\dfrac{\left(3^2\right)^{15}.\left(2^3\right)^{11}}{3^{29}.\left(2^4\right)^8}=\dfrac{3^{30}.2^{33}}{3^{29}.3^{32}}=3.2=6\)
\(\dfrac{2^{11}.9^3}{3^5.16^2}=\dfrac{2^{11}.\left(3^2\right)^3}{3^5.\left(2^4\right)^2}=\dfrac{2^{11}.3^6}{3^5.2^8}=2^3.3=8.3=24\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Có: \(\dfrac{\left(-3\right)^{10}x15^5}{25^3x\left(-9\right)^7}=\dfrac{3^{10}.\left(3.5\right)^5x}{-\left(3^2\right)^7\left(5^2\right)^3x}\)
\(=\dfrac{3^{15}.5^5x}{-3^{14}.5^6x}\)\(=\dfrac{3^{14}.5^5\left(3x\right)}{3^{14}.5^5\left(-5x\right)}=\dfrac{3x}{-5x}=-\dfrac{3}{5}\)
Vậy...
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Bài 10:
\(\dfrac{a+b}{a-b}=\dfrac{c+a}{c-a}\left(a\ne b\ne c\right)\\ \Leftrightarrow\left(a+b\right)\left(c-a\right)=\left(c+a\right)\left(a-b\right)\\ \Leftrightarrow ac-a^2+bc-ab=ac-bc+a^2-ab\\ \Leftrightarrow2a^2=2bc\\ \Leftrightarrow a^2=bc\)
Mình đg rất cần gấp giúp mình nhé