Bài 1:
ĐKXĐ: \(4-8x\ge0\Leftrightarrow x\le\dfrac{1}{2}\)
Bài 2:
a) \(=4.6-2.15=24-30=-6\)
b) \(=\sqrt{5}-\sqrt{3}+1+\sqrt{3}=1+\sqrt{5}\)
Bài 3:
a) ĐKXĐ: \(x\ge-\dfrac{1}{2}\)
\(pt\Leftrightarrow2x+1=49\Leftrightarrow2x=48\)
\(\Leftrightarrow x=24\left(tm\right)\)
b) ĐKXĐ: \(x\ge0\)
\(pt\Leftrightarrow\left(\sqrt{x}-4\right)^2=4\)
\(\Leftrightarrow\left[{}\begin{matrix}\sqrt{x}-4=2\\\sqrt{x}-4=-2\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}\sqrt[]{x}=6\\\sqrt{x}=2\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=36\left(tm\right)\\x=4\left(tm\right)\end{matrix}\right.\)
Bài 1:
\(ĐK:4-8x\ge0\Leftrightarrow x\le\dfrac{1}{2}\)
Bài 2:
\(a,=4\cdot6-2\cdot15=24-30=-6\\ b,=\sqrt{5}-\sqrt{3}+1+\sqrt{3}=\sqrt{5}+1\)
Bài 3:
\(a,ĐK:x\ge-\dfrac{1}{2}\\ PT\Leftrightarrow2x+1=49\Leftrightarrow x=24\left(tm\right)\\ b,ĐK:x\ge0\\ PT\Leftrightarrow\left(\sqrt{x}-6\right)\left(\sqrt{x}-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}\sqrt{x}=6\left(tm\right)\\\sqrt{x}=2\left(tm\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=36\\x=4\end{matrix}\right.\)
ĐK: \(4-8x\ge0\Leftrightarrow x\le\dfrac{1}{2}\)