Dọc theo chiều dài, ta trồng được:

\(5.5 : \frac{1}{4} = 22\) (khóm hoa)

Dọc theo chiều rộng, ta trồng được:

\(3 , 75 : \frac{1}{4} = 15\) (khóm hoa)

Như vậy, số khóm hoa trồng được dọc theo hai cạnh của mảnh vườn là:

\(\left[\right. \left(\right. 22 + 15 \left.\right) . 2 \left]\right. - 4 = 70\) (khóm hoa)

Vậy cần trồng 70 khóm hoa

a) = 1 : x= 0,75

= 1: 0,75 = 0,75

b) 2x = 1-1/2

2x = 1/2

x =1/4

a) = 2/3 *( 5/4- 3/4)

= 2/3* 1/2= 1/3​

\(b , 2. \left(\right. \frac{- 3}{2} \left.\right) - \frac{7}{2} = - 6. \frac{1}{2} - 7. \frac{1}{2} = \left(\right. - 6 - 7 \left.\right) . \frac{1}{2} = - 13. \frac{1}{2} = \frac{- 13}{2}\)

\(c , - \frac{3}{4} . 5 \frac{3}{13} - 0 , 75. \frac{36}{13} = - \frac{3}{4} . \left(\right. \frac{68}{13} - \frac{36}{13} \left.\right) = - \frac{3}{4} . \frac{32}{13} = - \frac{24}{13}\)

a)(1/2​+1,5)x=1/5​

\(2x=\frac{1}{5}\)

\(x=\frac{1}{10}\)

\(b \left.\right) \left(\right. - 1 \frac{3}{5} + x \left.\right) : \frac{12}{13} = 2 \frac{1}{6}\)

\(-\frac{8}{5}+x=\frac{13}{6}.\frac{12}{13}\)

\(-\frac{8}{5}+x=2\)

\(x=\frac{18}{5}\)

\(c \left.\right) \left(\right. x : 2 \frac{1}{3} \left.\right) . \frac{1}{7} = - \frac{3}{8}\)

\(x:\frac{7}{3}=-\frac{3}{8}:\frac{1}{7}\)

\(x=-\frac{21}{8}.\frac{7}{3}\)

\(x=-\frac{49}{8}\)

\(d \left.\right) - \frac{4}{7} x + \frac{7}{5} = \frac{1}{8} : \left(\right. - 1 \frac{2}{3} \left.\right)\)

\(-\frac{4}{7}x+\frac{7}{5}=-\frac{3}{40}\)

\(-\frac{4}{7}x=-\frac{59}{40}\)

\(x=\frac{413}{160}\)

a) \(\frac{1}{2} - \left(\right. x + \frac{1}{3} \left.\right) = \frac{5}{6}\)

\(x+\frac{1}{3}=\frac{1}{2}-\frac{5}{6}\)\(\)

\(x+\frac{1}{3}=-\frac{2}{6}\)

\(x=-\frac{2}{6}-\frac{1}{3}\)

\(x=-\frac{2}{3}\)

b) \(\left(\right. \frac{3}{8} - \frac{1}{5} \left.\right) + \left(\right. \frac{5}{8} - x \left.\right) = \frac{1}{5}\)\(\)

\(\frac{7}{40}+\left(\right.\frac{5}{8}-x\left.\right)=\frac{1}{5}\)

\(\frac{5}{8}-x=\frac{1}{5}-\frac{7}{40}\)

\(\frac{5}{8}-x=\frac{1}{40}\)

\(x=\frac{5}{8}-\frac{1}{40}\)

\(x=\frac{3}{5}\)

a) x=7-2/5+1,62

    x=8,22

b)23/5-x=3/10

x=23/5-3/10

x=43/10

c)2x-x=3/5+4/7

x=41/35

d) x=7/2-5/7+1/13-0,25

   x=951/364

a) A = [2/7(1/4-1/3)] : [ 2/7(1/3-2/5)]

=(1/4-1/3): (1/3-2/5)

= 1/1/4

A=3/5.6/7+3/7.3/5-2/7.3/5

A=3/5.(6/7+3/7-2/7)

A= 3/5.1

A=3/5

B =(-13.2/5+-2/9.2/5+11/9.2/5).5/2

B = 9-13-2/9+11/9).2/5.5/2

B = -13+(11/9-2/9)

B=-12

C=(-4/5+5/7).3/2+(-1/5+2/7).3/2

C = -4/5+5/7+-1/5+2/7).3/2

C = (-4/5+-1/5)+(5/7+2/7).3/2

C =-1+1.3/2

C =0

D =4/9:(1/15-10/15)+4/9:(2/22-5/22)

D = 4/9:-3/5+4/9:-3/22

D = 4/9.(-5/3+-22/3)

D=4/9.-27/3

D=-4

\(P=\) \(\frac23+\frac14+\frac35-\frac{7}{45}+\frac59+\frac{1}{12}+\frac{1}{35}\)

\(=\left(\frac23+\frac14+\frac{1}{12}\right)+\left(\frac59-\frac{7}{45}\right)+\frac35+\frac{1}{35}\)

\(=1+\frac43+\frac35+\frac{1}{35}\)

\(=2_{35}^1\)

\(Q=(5-6-2)+(\frac{-3}{4}-\frac74+\frac54)+(\frac15+\frac85-\frac{16}{5})\)

\(=-\left(3+\frac54+\frac75\right)\)

\(=\frac{113}{20}\)

A=(1/3​+2/3​)−(8/15​+7/15​)+(-1/7​+1/1/7​)=1−1+1=1;

B=(0.25−1/1/4​)+(3/5​+2/5​)−1/8

=( 1/4 - 1- 1/4) + 1 -1/8 = -1/8​
\(\).