\(\left(x-3\right)^3=27\)
\(\Leftrightarrow\left(x-3\right)^3=3^3\)
\(\Leftrightarrow x-3=3\Rightarrow x=6\)
\(\left(2x+1\right)^3=125\)
\(\Leftrightarrow\left(2x+1\right)^3=5^3\)
\(\Leftrightarrow2x+1=5\Rightarrow2x=4\Rightarrow x=2\)
\(2^x-15=17\)
\(\Leftrightarrow2^x=15+17=32\)
\(\Leftrightarrow x=5\)
\(\left(7x-11\right)^3=25.3^2+20\)
\(\left(7x-11\right)^3=245\)
\(\left(7x-11\right)^3=\sqrt[3]{245}\)
(lớp 6 chưa học cái này đề sai nhé)
\(2^{x+3}+2^x=36\)
\(2^x.2^3+2^x=36\)
\(2^x\left(2^3+1\right)=36\)
\(2^x.9=36\Rightarrow2^x=4\Rightarrow x=2\)
\(3^{x+4}+4+3^{x+2}=270\)
\(3^{x+4}+3^{x+2}=270-4=266\)
\(3^x.3^4+3^x.3^2=266\)
\(3^x\left(3^4+3^2\right)=266\)(đề cũng sai)
\(2.3^x=10.3^{12}+8.27^4\)
\(2.3^x=5314410+4251528\)
\(2.3^x=9565938\)
\(3^x=9565938:2=4782969\)
\(\Leftrightarrow x=14\)
\(\left(2x-5\right)^5=3^{10}\)
\(\Leftrightarrow\left(2x-5\right)^5=\left(3^2\right)^5\)
\(\left(2x-5\right)^5=9^5\)
\(\Leftrightarrow2x-5=9\Rightarrow2x=14\Rightarrow x=7\)