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Bài 1:
a)
\(\dfrac{4^2\cdot25^2+32\cdot125}{2^3\cdot5^2}\\ =\dfrac{\left(2^2\right)^2\cdot\left(5^2\right)^2+2^5\cdot5^3}{2^3\cdot5^2}\\ =\dfrac{2^{2\cdot2}\cdot5^{2\cdot2}+2^5\cdot5^3}{2^3\cdot5^2}\\ =\dfrac{2^4\cdot5^4+2^5\cdot5^3}{2^3\cdot5^2}\\ =\dfrac{2^4\cdot5^4}{2^3\cdot5^2}+\dfrac{2^5\cdot5^3}{2^3\cdot5^2}\\ =2\cdot5^2+2^2\cdot5\\ =2\cdot25+4\cdot5\\ =50+20\\ =70\)
c)
\(\dfrac{\left(1-\dfrac{4}{9}-2\right)\cdot16}{\left(2-3\right)^{-2}}+12\\ =\dfrac{\left(\dfrac{9}{9}-\dfrac{4}{9}-\dfrac{18}{9}\right)\cdot16}{\left(-1\right)^{-2}}+12\\ =\dfrac{\dfrac{-13}{9}\cdot16}{\dfrac{1}{\left(-1\right)^2}}+12\\ =\dfrac{\dfrac{-208}{9}}{1}+12\\ =\dfrac{-208}{9}+12\\ =\dfrac{-208}{9}+\dfrac{108}{9}\\ =\dfrac{100}{9}\)
Bài 2:
a)
\(\left(x+2\right)^2=36\\ \Rightarrow\left[{}\begin{matrix}x+2=6\\x+2=-6\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=4\\x=-8\end{matrix}\right.\)
b)
\(\left(1,78^{2x-2}-1,78^x\right):1,78^x=0\\ \Leftrightarrow\dfrac{1,78^{2x-2}}{1,78^x}-\dfrac{1,78^x}{1,78^x}=0\\ \Leftrightarrow\dfrac{1,78^{2x-2}}{1,78^x}-1=0\\ \Leftrightarrow \dfrac{1,78^{2x-2}}{1,78^x}=1\\ \Leftrightarrow1,78^{2x-2}=1,78^x\\ \Leftrightarrow2x-2=x\\ \Leftrightarrow2x-x=2\\ \Leftrightarrow x=2\)
d) \(5^{\left(x-2\right)\left(x+3\right)}=1\)
\(\Rightarrow5^{\left(x-2\right)\left(x+3\right)}=5^0\)
\(\Leftrightarrow\left(x-2\right)\left(x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\x+3=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2\\x=-3\end{matrix}\right.\)
Vậy \(x_1=-3;x_2=2\)
\(A=\dfrac{3^6\cdot3^8\cdot5^4-5^{13-9}\cdot3^{13}}{3^{12}\cdot5^6+3^{12}\cdot5^6}\)
\(=\dfrac{3^{14}\cdot5^4-5^4\cdot3^{13}}{3^{12}\cdot5^6\cdot2}\)
\(=\dfrac{3^{13}\cdot5^4\cdot2}{3^{12}\cdot5^6\cdot2}=\dfrac{3}{25}\)
\(B=\left(\dfrac{2}{5}\cdot5\right)^7+\left(\dfrac{9}{4}:\dfrac{3}{16}\right)^3=1+12^3=1729\)
a,76+75-74 =74.(72+7-1)=74.55
=>74.55 chia hết cho 55
=>76+75-74 chia hết cho 55
b)165+215=(24)5+215=220+215=215.(25+1)=215.33
=>215.3 chia hết cho 33
=>165+215 chia hết cho 33
a,76+75-74 =74.(72+7-1)=74.55
=>74.55 chia hết cho 55
=>76+75-74 chia hết cho 55
b)165+215=(24)5+215=220+215=215.(25+1)=215.33
=>215.3 chia hết cho 33
=>165+215 chia hết cho 33
câu 1
a(0,125)3x83=(0,125x8)3=13=1
b,2-(\(\frac{-3}{2}\))0+\(\frac{16}{4}:\frac{1}{2}\)=2-1+4:\(\frac{1}{2}\)=1+8=9
c\(^{3^5\cdot\frac{9}{3^7}\cdot2^0}\)=\(3^5\cdot\frac{3}{1}\cdot1=3^5\cdot3\cdot1=3^6\)
d,\(\frac{3}{2}-\frac{5}{6}:\left(\frac{1}{2}\right)^2=\frac{3}{2}-\frac{5}{6}:\frac{1}{4}=\frac{3}{2}-\frac{10}{3}=\frac{9}{6}-\frac{20}{6}=\frac{-11}{6}\)
câu 2
a\(\frac{x}{2}=\frac{4}{5}=\Rightarrow x\cdot5=2\cdot4\Rightarrow x=\frac{2.4}{5}=1,6\)
mình cần trả lời gấp vào thứ 3