Số khóm hoa cần trồng là:

(5,5\(+\)3,75).2:\(\dfrac{1}{4}\)=74 (khóm hoa)

Vậy số khóm hoa cần trồng là: 74 khóm hoa

a,\(\dfrac{1}{5}+\)\(\dfrac{4}{5}\):\(x\)=0,75

\(\dfrac{1}{5}+\dfrac{4}{5}:x=\dfrac{3}{4}\)

\(\dfrac{4}{5}:x=\dfrac{3}{4}-\dfrac{1}{5}\)

\(\dfrac{4}{5}:x=\dfrac{11}{20}\)

\(x=\dfrac{4}{5}:\dfrac{11}{20}\)

\(x=\dfrac{4}{5}.\dfrac{20}{11}\)

\(x=\dfrac{16}{11}\)

b,\(x+\)\(\dfrac{1}{2}\)=1\(-x\)

2.\(x=1-\)\(\dfrac{1}{2}\)

\(2.x=\dfrac{1}{2}\)

\(x=\dfrac{1}{2}:2\)

\(x=\dfrac{1}{4}\)

a,\(\dfrac{2}{3}\).\(\dfrac{5}{4}\)\(-\dfrac{3}{4}\).\(\dfrac{2}{3}\)=\(\dfrac{2}{3}\).(\(\dfrac{5}{4}\)\(-\dfrac{3}{4}\))=\(\dfrac{2}{3}\).\(\dfrac{1}{2}\)=\(\dfrac{1}{3}\)

b,2.\(\left(\dfrac{-3}{2}\right)^2\)\(-\dfrac{7}{2}\)=2.\(\dfrac{9}{4}\)\(-\dfrac{7}{2}\)=\(\dfrac{9}{2}\)\(-\dfrac{7}{2}\)=1

c,\(-\dfrac{3}{4}\).\(5\dfrac{3}{13}\)\(-0,75\).\(\dfrac{36}{13}\)=\(-\dfrac{3}{4}\).\(\dfrac{68}{13}\)\(-\dfrac{3}{4}\).\(\dfrac{36}{13}\)=\(-\dfrac{3}{4}\)(\(\dfrac{68}{13}\)\(+\dfrac{36}{13}\))=\(-\dfrac{3}{4}\).8=\(-6\)