a) \(0,25\left(x+\frac{1}{2}\right)+\frac{3}{4}+x=\frac{1}{2}\)
\(\Leftrightarrow0,25x+\frac{1}{8}+\frac{3}{4}+x=\frac{1}{2}\)
\(\Leftrightarrow1,25x=-\frac{3}{8}\)
\(\Leftrightarrow x=-\frac{3}{10}\)
c) \(2x^2+4x=0\)
\(\Leftrightarrow2x\left(x+2\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=0\\x+2=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=0\\x=-2\end{array}\right.\)
a) 0,25(x+1/2) + 3/4 + x= 1/2
<=> \(0,25x+\frac{1}{8}+\frac{3}{4}+x=\frac{1}{2}\)
<=> \(\frac{5}{4}x=\frac{1}{2}-\frac{1}{8}-\frac{3}{4}=-\frac{3}{8}\)
<=> x=\(-\frac{3}{10}\)
B) 1/2 ÷(x+7/5)-1/5=0.75
<=> \(\frac{1}{2}:\left(x+\frac{7}{5}\right)-\frac{1}{5}=\frac{3}{4}\)
<=> \(\frac{1}{2x}+\frac{5}{14}-\frac{1}{5}=\frac{3}{4}\)
<=> \(\frac{1}{2x}=\frac{3}{4}+\frac{1}{5}-\frac{5}{14}=\frac{83}{140}\)
<=> x=\(\frac{70}{83}\)
C) 2x^2 + 4x= 0
\(x\left(x+2\right)=0\)
<=> x=0 hoặc x=-2
D) x^2 + 4x = 0<=> x(x+4)=0
<=> x=0 hoặc x=-4
a) \(0,25\left(x+\frac{1}{2}\right)+\frac{3}{4}+x=\frac{1}{2}\)
\(\Rightarrow0,25x+\frac{1}{2}\cdot0,25+\frac{3}{4}+x=\frac{1}{2}\)
\(\Rightarrow0,25x+\frac{7}{8}+x=\frac{1}{2}\)
\(\Rightarrow0,25x+x=-\frac{3}{8}\)
\(\Rightarrow x\left(0,25+1\right)=-0,375\)
\(\Rightarrow1,25x=-0,375\Leftrightarrow x=-0,3\)
b) 1/2 ÷(x+7/5)-1/5=0,75
\(\Rightarrow\frac{1}{2}:\left(x+\frac{7}{5}\right)=0,95\)
\(\Rightarrow x+\frac{7}{5}=\frac{10}{19}\Leftrightarrow x=-\frac{83}{95}\)
C) 2x^2 + 4x= 0
=>x(2x+4)=0
=>x=0 hoặc 2x+4=0 =>2x=-4 <=>x=-2
=>x=0 hoặc x=-2
D) x^2 + 4x = 0
=>x(x+4)=0
=>x=0 hoặc x+4=0 <=>x=-4
=>x=0 hoặc x=-4