e) \(\left(x-3\right)\left(x^2+1\right)=0\)
\(\Rightarrow\left(x-3\right)=0\) ( \(x^2+1>0\forall x\))
\(\Rightarrow x=3\)
đ) \(4.8^2=2^x\)
\(2^2.\left(2^3\right)^2=2^x\)
\(2^2.2^6=2^x\)
\(2^8=2^x\)
\(\Rightarrow x=8\)
d) \(\left|x+3\right|=8\)
\(\Rightarrow\orbr{\begin{cases}x+3=8\\x+3=-8\end{cases}}\Rightarrow\orbr{\begin{cases}x=5\\x=-11\end{cases}}\)
mấy câu trên dễ rồi tự làm em nhé
a) 2x + 5=7
2x = 7-5
2x = 2
x = 2:2
x = 1
b) 4x - 13 = 2x +133
4x - 2x = 133 +13
2x = 146
x = 146: 2
x = 73
đ) 4.\(8^2=2^x\)
\(2^2.2^6=2^x\)
\(2^8=2^x\)
X = 8
\(2x+5=7\Leftrightarrow2x=2\Leftrightarrow x=1\)
\(4x-13=2x+133\Leftrightarrow4x-2x=133+13\Leftrightarrow2x=146\Leftrightarrow x=73\)
\(2.\left(5x-81\right)=4.\left(2x+31\right)+x\Leftrightarrow10x-162=8x+124\Leftrightarrow10x-8x=162+124\Leftrightarrow2x=288\Leftrightarrow x=144\)
\(\left|x+3\right|=8\Rightarrow\orbr{\begin{cases}x+3=8\\x+3=-8\end{cases}\Leftrightarrow\orbr{\begin{cases}x=5\\x=-11\end{cases}}}\)
\(4.8^2=2^x\Leftrightarrow2^2.\left(2^3\right)^2=2^x\Leftrightarrow2^2.2^6=2^x\Leftrightarrow2^8=2^x\Rightarrow x=8\)
\(\left(x-3\right).\left(x^2+1\right)=0\)
Mà \(x^2+1\ge1>0\Rightarrow x-3=0\Leftrightarrow x=3\)
