Ai trả lời nhanh tớ sẽ tick
Bài 1:
\(a,-3\dfrac{3}{4}+\dfrac{-10}{25}+\dfrac{-6}{12}\)
\(=\dfrac{-15}{4}-\dfrac{2}{5}-\dfrac{1}{2}\)
\(=\dfrac{-75}{20}-\dfrac{8}{20}-\dfrac{10}{20}\)
\(=\dfrac{\left(-75\right)-8-10}{20}\)
\(=\dfrac{-93}{20}\)
\(b,4-1\dfrac{2}{5}-\dfrac{8}{3}\)
\(=4-\dfrac{7}{5}-\dfrac{8}{3}\)
\(=\dfrac{60}{15}-\dfrac{21}{15}-\dfrac{40}{15}\)
\(=\dfrac{60-21-40}{15}\)
\(=\dfrac{-1}{15}\)
\(c,\dfrac{-5}{12}+1\dfrac{5}{18}-2,25\)
\(=\dfrac{-5}{12}+\dfrac{23}{18}-\dfrac{9}{4}\)
\(=\dfrac{-15}{36}+\dfrac{46}{36}-\dfrac{81}{36}\)
\(=\dfrac{\left(-15\right)+46-81}{36}\)
\(=\dfrac{-50}{36}=\dfrac{-25}{18}\)
\(d,-0,6-\dfrac{-4}{9}-\dfrac{16}{15}\)
\(=-\dfrac{3}{5}+\dfrac{4}{9}-\dfrac{16}{15}\)
\(=\dfrac{-27}{45}+\dfrac{20}{45}-\dfrac{48}{45}\)
\(=\dfrac{-55}{45}=\dfrac{-11}{9}\)
\(e,-1\dfrac{2}{3}+\dfrac{3}{4}-\dfrac{1}{2}+2\dfrac{1}{6}\)
\(=\dfrac{-5}{3}+\dfrac{3}{4}-\dfrac{1}{2}+\dfrac{13}{6}\)
\(=\dfrac{-20}{12}+\dfrac{9}{12}-\dfrac{6}{12}+\dfrac{26}{12}\)
\(=\dfrac{\left(-20\right)+9-6+26}{12}\)
\(=\dfrac{9}{12}=\dfrac{3}{4}\)
( Lần sau bn chú ý tách nhỏ ra nha, nhìn v nó rất là khó và cậu còn chụp ngang nx nên rất là khó làm)
Bài 5:
a: \(-\dfrac{1}{10}+\dfrac{2}{5}x+\dfrac{7}{20}=\dfrac{1}{10}\)
=>\(\dfrac{2}{5}x+\dfrac{7}{20}-\dfrac{2}{20}=\dfrac{2}{20}\)
=>\(\dfrac{2}{5}x=\dfrac{2}{20}+\dfrac{2}{20}-\dfrac{7}{20}=-\dfrac{3}{20}\)
=>\(x=-\dfrac{3}{20}:\dfrac{2}{5}=-\dfrac{3}{20}\cdot\dfrac{5}{2}=-\dfrac{15}{40}=-\dfrac{3}{8}\)
b: \(\dfrac{1}{3}+\dfrac{1}{2}:x=-\dfrac{1}{5}\)
=>\(\dfrac{1}{2}:x=-\dfrac{1}{5}-\dfrac{1}{3}=-\dfrac{8}{15}\)
=>\(x=-\dfrac{1}{2}:\dfrac{8}{15}=-\dfrac{1}{2}\cdot\dfrac{15}{8}=-\dfrac{15}{16}\)
c: \(-\dfrac{2}{3}:x+\dfrac{5}{8}=-\dfrac{7}{12}\)
=>\(-\dfrac{2}{3}:x=-\dfrac{7}{12}-\dfrac{5}{8}=\dfrac{-14}{24}-\dfrac{15}{24}=-\dfrac{29}{24}\)
=>\(x=\dfrac{29}{24}:\dfrac{2}{3}=\dfrac{29}{24}\cdot\dfrac{3}{2}=\dfrac{29}{8\cdot2}=\dfrac{29}{16}\)
d: \(\dfrac{1}{2}x+2\dfrac{1}{2}=3\dfrac{1}{2}x-\dfrac{3}{4}\)
=>\(\dfrac{1}{2}x+\dfrac{5}{2}=\dfrac{7}{2}x-\dfrac{3}{4}\)
=>\(\dfrac{7}{2}x-\dfrac{1}{2}x=\dfrac{5}{2}+\dfrac{3}{4}\)
=>\(3x=\dfrac{10}{4}+\dfrac{3}{4}=\dfrac{13}{4}\)
=>\(x=\dfrac{13}{4}:3=\dfrac{13}{12}\)
e: \(\dfrac{2}{3}x-\dfrac{2}{5}=\dfrac{1}{2}x-\dfrac{1}{3}\)
=>\(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{1}{3}-\dfrac{2}{5}\)
=>\(\dfrac{4}{6}x-\dfrac{3}{6}x=\dfrac{5}{15}-\dfrac{6}{15}\)
=>\(\dfrac{1}{6}x=-\dfrac{1}{15}\)
=>\(x=-\dfrac{1}{15}:\dfrac{1}{6}=-\dfrac{6}{15}=-\dfrac{2}{5}\)
f: \(\dfrac{1}{3}x+\dfrac{2}{5}\left(x+1\right)=0\)
=>\(\dfrac{1}{3}x+\dfrac{2}{5}x+\dfrac{2}{5}=0\)
=>\(\dfrac{5}{15}x+\dfrac{6}{15}x=-\dfrac{2}{15}\)
=>\(\dfrac{11}{15}x=-\dfrac{2}{15}\)
=>11x=-2
=>\(x=-\dfrac{2}{11}\)
