Question

Tìm x: a)128-3.(x+4)=23

b)(158-x):7=20

Answer 1

a) \(128-3\cdot\left(x+4\right)=23\)

\(\Leftrightarrow3\cdot\left(x+4\right)=105\)

\(\Leftrightarrow x+4=35\)

\(\Leftrightarrow x=31\)

b) \(\left(158-x\right):7=20\)

\(\Leftrightarrow158-x=140\)

\(\Leftrightarrow x=18\)

Answer 2

\(a,128-3.\left(x+4\right)=23\)                                                      

\(\Rightarrow3.\left(x+4\right)=128-23\)

\(\Rightarrow3.\left(x+4\right)=105\)

\(\Rightarrow\left(x+4\right)=105:3\)

\(\Rightarrow\left(x+4\right)=35\)

\(\Rightarrow x=35-4\)

\(\Rightarrow x=31\)

Answer 3

\(b,\left(158-x\right):7=20\)

\(\Rightarrow\left(158-x\right)=20.7\)

\(\Rightarrow\left(158-x\right)=140\)

\(\Rightarrow x=158-140\)

\(\Rightarrow x=18\)

Answer 4

Tìm x:

a)128-3.(x+4)=23

3(x+4)=128-23

3(x+4)=105

x+4=105:3

x+4=35

    x=35-4

    x=31

b)(158-x):7=20

158-x=20x7

158-x=140

       x=158-140

       x=18