Question

Tìm x :

a) 3x + 7 = 2x - 11

b) 4 - x = 2x + 16

c) -(x - 4 ) = x + 8

Help me !!!!!!!!!!!

Answer 1

a, 3x + 7 = 2x - 11

\(\Rightarrow3x-2x=-11-7\)

\(\Rightarrow x=-18\)

b, 4 - x = 2x + 16

\(\Rightarrow-x-2x=16-4\)

\(\Rightarrow-3x=12\)

\(\Rightarrow x=\frac{12}{-3}\)

\(\Rightarrow x=-4\)

c, -(x - 4) = x + 8

\(\Rightarrow-x+4=x+8\)

\(\Rightarrow-2x=4\)

\(\Rightarrow x=\frac{4}{-2}\)

\(\Rightarrow x=-2\)

Answer 2

Nguyễn Huy Thắng

Nguyễn Huy Tú

Answer 3

Nguyễn Xuân Sáng

Answer 4

a ) \(3x+7=2x-11\)

\(\Leftrightarrow3x-2x=-11-7\)

\(\Leftrightarrow x=-18\)

b ) \(4-x=2x+16\)

\(\Leftrightarrow-x-2x=16-4\)

\(\Leftrightarrow-3x=12\)

\(\Leftrightarrow x=-4\)

c ) \(-\left(x-4\right)=x+8\)

\(\Leftrightarrow-x+4=x+8\)

\(\Leftrightarrow-2x=4\)

\(\Leftrightarrow x=-2\)