a) Ta có : 16x = 2100
=> (24)x = 2100
=> 24x = 2100
=> 4x = 100
=> x = 25
b) 5x = 125
=> 5x = 53
=> x = 3
Bg
a)16x = 2100
(24)x = 2100
24.x = 2100 (100 =4.25)
24.x = 24.25
x = 25
b) 5x = 125
5x = 53
x = 3
\(a,16^x=2^{100}\)
\(\Rightarrow2^{4x}=2^{100}\)
\(\Leftrightarrow4x=100\)
\(\Leftrightarrow x=100:4\)
\(\Leftrightarrow x=25\)
Vậy \(x=25\)
\(b.5^x=125\)
\(\Rightarrow5^x=5^3\)
\(\Rightarrow x=3\)
Học tốt
2^4x=2^100
4x=100
x=100:4
x=25
vậy x=25
5^x=5^3
x=3
vậy x=3
Trả lời:
a, \(16^x=2^{100}\)
\(\Leftrightarrow\left(2^4\right)^x=2^{100}\)
\(\Leftrightarrow2^{4x}=2^{100}\)
\(\Leftrightarrow4x=100\)
\(\Leftrightarrow x=25\)
Vậy \(x=25\)
b, \(5^x=125\)
\(\Leftrightarrow5^x=5^3\)
\(\Leftrightarrow x=3\)
Vậy \(x=3\)