13 x 3 - 2 = 13 : S

180 + 30 : 6 = 35 : S

30 + 60 x 2 = 180 : S

282 - 100 : 2 = 232 : Đ

\(\dfrac{7}{16}+\dfrac{-1}{8}+\dfrac{9}{32}=\dfrac{14}{32}-\dfrac{4}{32}+\dfrac{9}{32}=\dfrac{19}{32}\)

\(\dfrac{5}{4}-\dfrac{25}{30}\times\dfrac{37}{44}+\dfrac{-25}{30}\times\dfrac{13}{44}+\dfrac{-25}{30}\times\dfrac{-6}{44}\)

\(=-\dfrac{25}{30}\times\left(\dfrac{5}{4}+\dfrac{37}{44}+\dfrac{13}{44}-\dfrac{6}{44}\right)\)

\(=-\dfrac{25}{30}\times\left(\dfrac{55}{44}+\dfrac{37}{44}+\dfrac{13}{44}-\dfrac{6}{44}\right)\)

\(=-\dfrac{25}{30}\times\dfrac{99}{44}\)

\(=-\dfrac{5}{6}\times\dfrac{9}{4}\)

\(=-\dfrac{15}{8}\)

\(\left(\dfrac{7}{16}+\dfrac{-1}{8}+\dfrac{9}{32}\right):\dfrac{5}{4}\)

\(=\left(\dfrac{14}{32}+\dfrac{-4}{32}+\dfrac{9}{32}\right):\dfrac{5}{4}\)

\(=\dfrac{19}{32}:\dfrac{5}{4}\)

\(=\dfrac{19}{32}.\dfrac{4}{5}=\dfrac{19.4}{32.5}=\dfrac{19}{40}\)

\(\dfrac{-25}{30}.\dfrac{37}{44}+\dfrac{-25}{30}.\dfrac{13}{44}+\dfrac{-25}{30}.\dfrac{-6}{44}\)

\(=\dfrac{-25}{30}.\left(\dfrac{37}{44}+\dfrac{13}{44}+\dfrac{-6}{44}\right)\)

\(=\dfrac{-25}{30}.\dfrac{44}{44}=\dfrac{-5}{6}.1=-\dfrac{5}{6}\)

-30 + x=13

x=13+30

x=43

a) Ta có: (-30)-(-x)=13

\(\Leftrightarrow-30+x=13\)

\(\Leftrightarrow x-30=13\)

\(\Leftrightarrow x=13+30=43\)

Vậy: x=43

a: =1/6+17/6-4/13+30/13

=3+2

=5

b: =28,8:3,25*2,5

=72:3,25

=288/13

X+3/10X=(-13/10)

X(1+3/10)=(-13/10)

X13/10=(-13/10)

X=(-13/10):13/10

X=-1

\(12+13=30-x\)

\(25=30-x\)

\(\Rightarrow x=5\)

\(12+13=30-x\)

\(25=30-x\)

\(x=30-25\)

\(x=5\)

B

b