Question

tinh x 

a - 420 : ( x : 39 ) = 105

b - 200 - 18 : ( 372 : 3 x - 1 ) - 28 = 166

Answer 1

a) -420 :(x:39)=105

x:39=-420 : 105

x : 39=\(\dfrac{-14}{5}\)

x=\(\dfrac{-546}{5}\)

Answer 2

a - 420 : ( x : 39 ) = 105
⇒ x : 39 = 420 : 105

⇒ x : 39 = 4

⇒ x = 4 * 39

⇒ x = 156

Answer 3

b)-200 -18 :(372 : x-1)-28=166

-200-18 :(372:x-1)=194

18:(372:x-1)=-200-194

18:(372:x-1)=-394

372:x-1=-9/197

372:x=-9/197+1

372:x=188/197

x=\(\dfrac{18321}{47}\)

Answer 4

a: Ta có: \(-420:\left(x:39\right)=105\)

\(\Leftrightarrow x:39=-4\)

hay x=-156

b: Ta có: \(-228-18:\left(372:3x-1\right)=166\)

\(\Leftrightarrow-18:\left(372:3x-1\right)=166+228=394\)

\(\Leftrightarrow372:3x-1=-\dfrac{9}{197}\)

\(\Leftrightarrow372:3x=\dfrac{188}{197}\)

\(\Leftrightarrow3x=\dfrac{18321}{47}\)

hay \(x=\dfrac{6107}{47}\)

Answer 5

a - 420 : ( x : 39 ) = 105
⇒ x : 39 = 420 : 105

⇒ x : 39 = 4

⇒ x = 4 * 39

⇒ x = 156