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a) \(3^3 : 3^2\)=\(3^{3-2}=3^1\)
b) \(5^{4} : 5^{2}\)=\(5^{4-2}=5^2\)
c) \(8^{3} . 8^{2}\)=\(8^{3+2}=8^5\)
d) Cách 1:
\(5^{4} . 5^{3}: 5^{2}=5^{4+3}:5^2=5^7:5^2=5^{7-2}=5^5\)
Cách 2:
\(5^{4} . 5^{3}: 5^{2}=5^{4+3-2}=5^5\)
a)3^3-2=3
b)625/25=25=5^2
c)8^3+2=8^5
d)5^4+3/5^2=5^7:5^2=5^7-2=5^5
Bài 1:
a) \(8^5\cdot8^2=8^7\)
b) \(9^3\cdot3^2=\left(3^2\right)^3\cdot3^2=3^6\cdot3^2=3^8\)
c) \(2^7\cdot5^7=10^7\)
d) \(27^6:3^3=\left(3^3\right)^6:3^3=3^{18}:3^3=3^{15}\)
Bài 2:
a) \(x^6:x^3=125\)
\(\Rightarrow x^3=125\)
\(\Rightarrow x=5\)
b) \(x^{20}=x\)
\(\Rightarrow x^{20}-x=0\)
\(\Rightarrow x\left(x^{19}-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x^{19}-1=0\Rightarrow x=1\end{matrix}\right.\)
c) \(3^x\cdot3=243\)
\(\Rightarrow3^x=81\)
\(\Rightarrow x=4\)
d) \(2x-138=2^3\cdot3^2\)
\(\Rightarrow2x-138=72\)
\(\Rightarrow2x=200\)
\(\Rightarrow x=100\)
Giải:
Bài 1:
a) \(8^5.8^2=8^{5+2}=8^7\)
b) \(9^3.3^2=3^6.3^2=3^{6+2}=3^8\)
c) \(2^7.5^7=\left(2.5\right)^7=10^7\)
d) \(27^6:3^3=3^{18}:3^3=3^{18-3}=3^{15}\)
Bài 2:
a) \(x^6:x^3=x^{6-3}=x^3=125\)
\(\Leftrightarrow x=5\)
b) \(x^{20}=x\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\\x=1\end{matrix}\right.\)
c) \(3^x.3=243\)
\(\Leftrightarrow3^{x+1}=243\)
\(\Leftrightarrow3^{x+1}=3^5\)
\(\Leftrightarrow x+1=5\Leftrightarrow x=4\)
d) \(2.x-138=2^3.3^2\)
\(\Leftrightarrow2.x-138=8.9\)
\(\Leftrightarrow2.x-138=72\)
\(\Leftrightarrow2.x=72+138\)
\(\Leftrightarrow2.x=210\Leftrightarrow x=105\)
Chúc bạn học tốt!
1.
a) \(3^4\times3^5\times3^6=3^{4+5+6}=3^{15}\)
b) \(5^2\times5^4\times5^5\times25=5^2\times5^4\times5^5\times5^2=5^{2+4+5+2}=5^{13}\)
c) \(10^8\div10^3=10^{8-3}=10^5\)
d) \(a^7\div a^2=a^{7-2}=a^5\)
2.
\(987=900+80+7\\ =9\times100+8\times10+7\\ =9\times10^2+8\times10^1+7\times10^0\)
\(2021=2000+20+1\\ =2\times1000+2\times10+1\times1\\ =2\times10^3+2\times10^1+1\times10^0\)
\(abcde=a\times10000+b\times1000+c\times100+d\times10+e\times1\\ =a\times10^4+b\times10^3+c\times10^2+d\times10^1+e\times10^0\)
\(5^2.5^3=5^{2+3}=5^5\)
\(b^2.b^3=b^{2+3}=b^5\)
\(x^4.x^5+y^2.y=x^{4+5}+y^{2+1}=x^9+y^3\)
\(27^3.9^4.243=\left(3^3\right)^3.\left(3^2\right)^4.3^5=3^9.3^8.3^5=3^{9+8+5}=3^{22}\)
Nhớ k cho mình nhé! Thank you!!!
a) 52 × 53 = 55
b) b2 × b3 = b5
c) x4 × x5 + y2 × y = x9 + y3
d) 273 × 94 × 243 = 322