\(A=0,25+\dfrac{3}{5}-\left(\dfrac{1}{8}-\dfrac{2}{5}+2\dfrac{1}{4}\right)\)
\(=\dfrac{1}{4}+\dfrac{3}{5}-\dfrac{1}{8}+\dfrac{2}{5}-2-\dfrac{1}{4}\)
\(=1-\dfrac{1}{8}-2=-\dfrac{9}{8}\).
\(A=0,25+\dfrac{3}{5}-\left(\dfrac{1}{8}-\dfrac{2}{5}+2\dfrac{1}{4}\right)\)
\(A=\dfrac{1}{4}+\dfrac{3}{5}-\left(\dfrac{1}{8}-\dfrac{2}{5}+\dfrac{9}{4}\right)\)
\(A=\dfrac{5}{20}+\dfrac{12}{20}-\left(\dfrac{5}{40}-\dfrac{16}{40}+\dfrac{90}{40}\right)\)
\(A=\dfrac{17}{20}-\left(\dfrac{5-16+90}{40}\right)=\dfrac{17}{20}-\dfrac{79}{40}=\dfrac{34}{40}-\dfrac{79}{40}=-\dfrac{45}{40}=-\dfrac{9}{8}\)
Vậy A = \(-\dfrac{9}{8}\)
\(A=0,25+\dfrac{3}{5}-\left(\dfrac{1}{8}-\dfrac{2}{5}+2+\dfrac{1}{4}\right)\)
\(A=\dfrac{1}{4}+\dfrac{3}{5}-\dfrac{1}{8}+\dfrac{2}{5}-2-\dfrac{1}{4}\)
\(A=\left(\dfrac{1}{4}-\dfrac{1}{4}\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)-\left(\dfrac{1}{8}+2\right)\)
\(A=1-2-\dfrac{1}{8}=-1\dfrac{1}{8}\)
tik mik nha!!