a, \(\left(x-1\right)^3=125\)
\(\Rightarrow x-1=5\Rightarrow x=6\)
b, \(\left(2x+1\right)^3=343\)
\(\Rightarrow2x+1=7\Rightarrow x=3\)
c, \(\left(7x-11\right)^3=2^5.5^2+200\)
\(\Rightarrow\left(7x-11\right)^3=32.25+200\)
\(\Rightarrow\left(7x-11\right)^3=1000\)
\(\Rightarrow7x-11=10\Rightarrow x=3\)
Chúc bạn học tốt!!!
a) \(\left(x-1\right)^3=125\Leftrightarrow\left(x-1\right)^3=5^3\Rightarrow x-1=5\)
\(\Leftrightarrow x=6\) vậy \(x=6\)
b) \(\left(2x+1\right)^3=343\Leftrightarrow\left(2x+1\right)^3=7^3\Rightarrow2x+1=7\)
\(\Leftrightarrow2x=6\Leftrightarrow x=\dfrac{6}{2}=3\) vậy \(x=3\)
c) \(\left(7x-11\right)^3=2^5.5^2+200\Leftrightarrow\left(7x-11\right)^3=32.25+200\)
\(\Leftrightarrow\left(7x-11\right)^3=800+200=1000=10^3\Rightarrow7x-11=10\)
\(\Leftrightarrow7x=21\Leftrightarrow x=\dfrac{21}{7}=3\) vậy \(x=3\)
\(\left(x-1\right)^3=125\)
\(\Rightarrow\left(x-1\right)^3=5^3\)
\(\Rightarrow x-1=5\)
\(\Rightarrow x=6\)
\(\left(2x+1\right)^3=343\)
\(\Rightarrow\left(2x+1\right)^3=7^3\)
\(\Rightarrow2x+1=7\)
\(\Rightarrow2x=6\)
\(\Rightarrow x=3\)
\(\left(7x-11\right)^3=2^5.5^2+200\)
\(\Rightarrow\left(7x-11\right)^3=32.25+200\)
\(\Rightarrow\left(7x-11\right)^3=1000\)
\(\Rightarrow\left(7x-11\right)^3=10^3\)
\(\Rightarrow7x-11=10\)
\(\Rightarrow7x=21\)
\(\Rightarrow x=3\)
a)\(^{\left(x-1\right)^3}\)=125
\(\Rightarrow\)\(^{\left(x-1\right)^3}\)=\(^{5^3}\)
\(\Rightarrow\)x-1=5
x=5+1
x=6
b)(2.\(x\)+1)\(^{^3}\)=343
(2.x+1)\(^{^3}\)=\(^{7^3}\)
2.x+1 =7
2.x =7-1
2.x =6
x =6:2
x =3
c)(7.x-11)\(^3\)=\(^{2^5}\).\(^{5^2}\)+200
(7.x-11)\(^3\)=800+200
(7.x-11)\(^3\)=1000
(7.x-11)\(^3\)=\(^{10^3}\)
7.x-11=10
7.x =10+11
7.x =21
x =21:7
x =3
Chúc bạn học tốt nha!
