Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
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!
a. 2x . 7 = 56
2x = 56 : 7
2x = 8
\(\Rightarrow\)23 = 8
Vậy x = 8
2x x 16 = 128
2x = 128 : 16
2 x = 8
2x = 23
3x : 9 = 27
3x = 27 x 9
3x =243
3x = 35
[ 2x + 1 ]3 = 27
2x3 + 13 = 27
2x3 +1 = 27
2x3 = 27 - 1
2x3 = 26
a)7^3.25-7^3.18
=7^3.(25-18)
=7^3.7
=7^3+1
=7^4
b)2^4.15-[173-(14-9)^2]
=16.15-[173-5^2]
=240-[173-25]
=240-148
=92
c)53.147+53^2+47.200
=53.147+53.53+47.200
=53.(147+53)+47.200
=53.200+47.200
=200.(53+47)
=200.100
=20000
d)36:{280:[240-(95+3.25)]}
=36:{280:[240-(95+75)]}
=36:{280:[240-170]}
=36:{280:70}
=36:4
=9
a, 39 x 213 + 87 x 39
= 39 x ( 213 + 87)
= 39 x 300
= 11700
b. 27 x 75 + 25 x 27 - 150
= 27 x ( 75 + 25 ) - 150
= 27 x 100 - 150
= 2700 - 150
= 2550
a) 39 x 213 + 87 x 39
= 39 x ( 213 + 87 )
= 39 x 300
= 11700
b) 27 x 75 + 25 x 27 - 150
= 27 x ( 75 + 25 ) - 150
= 27 x 100 - 150
= 2700 - 150
= 2550
\(12x-33=3^2.3^3\)
\(\Rightarrow12x-33=3^5\)
\(\Rightarrow12x-33=243\)
\(\Rightarrow12x=243+33\)
\(\Rightarrow12x=276\)
\(\Rightarrow x=276:12\)
\(\Rightarrow x=23\)
tíc mình nha
2, 27.75+25.27-150
=27.(75+25) - 150
=27.100 -15.10
=27.10.10 - 15.10
=10.(27.10 -15)
=10.(270-15)
=10.255
=2550