\(-\dfrac{7}{12}\cdot\dfrac{3}{8}+-\dfrac{7}{12}\cdot\dfrac{5}{8}+1\dfrac{7}{12}\)

\(=-\dfrac{7}{12}\cdot\left(\dfrac{3}{8}+\dfrac{5}{8}-1\right)\)

\(=-\dfrac{7}{12}\cdot\left(\dfrac{8}{8}-1\right)\)

\(=-\dfrac{7}{12}\cdot\left(1-1\right)\)

\(=-\dfrac{7}{12}\cdot0\)

\(=0\)

\((\)125-120\()\)x45

5x45=225

\(\dfrac{30x25x7x8}{75x8x12x14}\)=\(\dfrac{10\cdot1\cdot7\cdot1}{1\cdot1\cdot1\cdot12\cdot2}\)=\(\dfrac{70}{24}\)

B

b

b

a)\(\dfrac{x}{60}=-\dfrac{3}{4}\)

\(\Rightarrow x\cdot4=60\cdot\left(-3\right)\)

   \(x\cdot4=-180\)

  x=45

b)\(\dfrac{2}{5}=\dfrac{12}{x}\)

   \(\Rightarrow2x=5\cdot12\)

      \(2x=60\)

       x=30

c)\(x-\dfrac{5}{7}=\dfrac{6}{21}\)

      \(x=\dfrac{2}{7}+\dfrac{5}{7}\)

      x=1

d)\(x+\dfrac{7}{8}=\dfrac{63}{24}\)

     \(x=\dfrac{21}{8}-\dfrac{7}{8}\)

     \(\dfrac{14}{8}\)

a)\(\dfrac{x}{60}=\dfrac{-3}{4}\Rightarrow x=\dfrac{-3.60}{4}=-45\)

b)\(\dfrac{2}{5}=\dfrac{12}{x}\Rightarrow x=\dfrac{5.12}{2}=30\)

a) 5 x 8 x 7 = 280

b) 12 + 12 + 12 = 36

a) 5 x 8 x 7

= 40 x 7

= 280

b) 12 + 12 + 12 

= 12 x 3

= 36

a) 280

b) 36