\(50\%.\frac{4}{3}.10.\frac{7}{35}.0,75\)

\(=\frac{1}{2}.\frac{4}{3}.10.\frac{7}{35}.\frac{3}{4}\)

\(=\left(\frac{1}{2}.10\right)\times\left(\frac{4}{3}.\frac{3}{4}\right).\frac{7}{35}\)

\(=5.1.\frac{7}{35}\)

\(=\frac{35}{35}=1\)

~ Hok tốt ~

\(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{40.43}\)

\(=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{40}-\frac{1}{43}\)

\(=1+\left(\frac{1}{4}-\frac{1}{4}\right)+\left(\frac{1}{7}-\frac{1}{7}\right)+...+\left(\frac{1}{40}-\frac{1}{40}\right)-\frac{1}{43}\)

\(=1-\frac{1}{43}=\frac{42}{43}\)

~ Hok tốt ~

câu a) có trong đề cương của tui 

501.1/3.10.7/35.0,75 = 501.1/3.10.1/5.75/100

                            = 250 / 1 /2

50% x 11/3 x 10 x 7 /35 x 0,75 = 2, 75 

a, \(\frac{-5}{7}.\frac{2}{11}+\frac{-5}{7}.\frac{9}{11}.\frac{12}{7}\)

\(=\frac{-5}{7}.\left(\frac{2}{11}+\frac{9}{11}\right)+\frac{12}{7}\)

\(=\frac{-5}{7}.1+\frac{12}{7}=\frac{-5}{7}+\frac{12}{7}=\frac{7}{7}=1\)

Kết quả = 1

B= 0,5 .4/3 .(-10) .0,75 .7/-35

B= 1/2 .4/3 .(-10) .3/4 .(-1)/5

B= [1/2 .(-1)/5 .(-10) ] .(4/3 .3/4)

B= 1 .1

B= 1

=1 nha

K MK NHA. CHÚC BẠN HỌC GIỎI

bn làm rõ 1 chút đi