Question

tìm x thuộc z bt :

a) 4(x+1)-(3x+1)=14

b)-2(x-1)-(2-3x)=2.(x+1)-4

c)-(x-3)+(4x-1)-14=2(x-2)-5

Answer 1

Giải:

a) \(4\left(x+1\right)-\left(3x+1\right)=14\)

\(\Leftrightarrow4x+4-3x-1=14\)

\(\Leftrightarrow x+3=14\)

\(\Leftrightarrow x=14-3=11\)

Vậy ...

b) \(-2\left(x-1\right)-\left(2-3x\right)=2\left(x+1\right)-4\)

\(\Leftrightarrow-2x+2-2+3x=2x+2-4\)

\(\Leftrightarrow x=2x-2\)

\(\Leftrightarrow x-2x=-2\)

\(\Leftrightarrow-x=-2\)

\(\Leftrightarrow x=2\)

Vậy ...

c) \(-\left(x-3\right)+\left(4x-1\right)-14=2\left(x-2\right)-5\)

\(\Leftrightarrow-x+3+4x-1-14=2x-4-5\)

\(\Leftrightarrow3x-15=2x-9\)

\(\Leftrightarrow3x-2x=-9+15\)

\(\Leftrightarrow x=6\)

Vậy ...