Answer :
[tex]{ \qquad\qquad\huge\underline{{\sf Answer}}} [/tex]
Here's the solution ~
[tex]\qquad \sf \dashrightarrow \: 4x - 6 = x + 9[/tex]
[tex]\qquad \sf \dashrightarrow \: 4x - x = 9 + 6[/tex]
[tex]\qquad \sf \dashrightarrow \: 3x = 15[/tex]
[tex]\qquad \sf \dashrightarrow \: x = 15 \div 3[/tex]
[tex]\qquad \sf \dashrightarrow \: x = 5[/tex]