Bài 3:
a: \(3^x=9\)
nên x=2
b: \(5^x=125\)
nên x=3
c: \(3^{x+1}=9\)
nên x+1=2
hay x=1
d: \(6^{x+1}=36\)
nên x+1=2
hay x=1
e: \(3^{2x+1}=27\)
=>2x+1=3
hay x=1
f: \(x^{50}=x\)
nên \(x^{50}-x=0\)
=>x(x-1)=0
=>x=0 hoặc x=1
baif 3
a)\(3^x=9\Leftrightarrow3^x=3^2\Rightarrow x=2\)
b)\(5^x=125\Leftrightarrow5^x=5^3\Rightarrow x=3\)
c)\(3^{x+1}=9\Leftrightarrow3^{x+1}=3^{1+1}\Rightarrow x=1\)
d)\(6^{x-1}=36\Leftrightarrow6^{x-1}=6^{3-1}\Rightarrow x=3\)
e)\(3^{x+1}=27\Leftrightarrow3^{x+1}=3^{2+1}\Rightarrow x=2\)
g)\(x^{50}=x\Rightarrow x^{50}:x=1\Rightarrow x^{49}=1\Rightarrow x=1\)
hoặc \(x^{50}-x=0\Rightarrow\left[{}\begin{matrix}x=1\\x=0\end{matrix}\right.\)
Refer:
1,
a) {145 -[130 -(246 - 236)]: 2}. 5
= {145 -[130 - 10]: 2}. 5
= {145 - 120 : 2}. 5
= {145 - 60}. 5
= 85 .5
=425
b) 100 :{250 :[450 -(4 . 5³ - 2² . 25)]}
= 100 :{250 :[450 -(4 . 125 - 4 . 25)]}
= 100 :{250 :[450 -(4 .(125 - 25)]}
= 100 :{250 :[450 -(4 . 100)]}
= 100 :{250 :[450 - 400]}
= 100 :{250 : 50}
= 100 : 5
= 20
c) 325 - 5 .[4³ -(27 - 5²): 1^18]
= 325 - 5 .[64 -(27 - 25): 1]
= 325 - 5 .[64 - 2 : 1]
= 325 - 5 . 62
= 325 - 310
= 15
d) 17^0 -[5^13 : 5^11 +(135 - 130)³]
= 1 -[5^13-11 +(135 - 130)³]
= 1 -[5² + 5³]
= 1 -[25 + 125]
= 1 - 150
= -149
Bài 2)
a)
\(\left(x-5\right).2=16\)
\(x-5=16:2\)
\(x-5=8\)
\(x=8+5\)
\(x=13\)
b)
\(6x-6=24\)
\(6x=30\)
\(x=30:6\)
\(x=5\)
c)
\(23+x.2=37\)
\(x.2=37+23\)
\(x.2=60\)
\(x=60:2\)
\(x=30\)
d)
\(\left(x.7-7\right).\left(x.12-24\right)=0\)
\(=>\left[{}\begin{matrix}x.7-7=0\\x.12-24=0\end{matrix}\right.=>\left[{}\begin{matrix}x.7=7\\x.24=24\end{matrix}\right.=>\left[{}\begin{matrix}x=1\\x=1\end{matrix}\right.\)
e)
\(140.10.x=120\)
\(10.x=120:140\)
\(10.x=\dfrac{6}{7}\)
\(x=\dfrac{6}{7}:10\)
\(x=\dfrac{3}{35}\)
g)
\(x.5-127=275\)
\(x.5=275+127\)
\(x.5=402\)
\(x=402:5\)
\(x=\dfrac{402}{5}=80.4\)
