Multiply both sides by 4 and then 3 to cancel out the fractions. Then, use the distributive property to get like terms and isolate x:
1/4(x+6)=1/6(x+8)
color(blue)(4*)1/4(x+6)=color(blue)(4*)1/6(x+8)
color(red)cancelcolor(black)(color(blue)(4*)1/4)(x+6)=color(blue)(4*)1/6(x+8)
x+6=color(blue)4/6(x+8)
x+6=color(blue)2/3(x+8)
color(blue)(3*)(x+6)=color(blue)(3*)color(blue)2/3(x+8)
color(blue)(3*)(x+6)=color(blue)(color(red)cancelcolor(blue)3*)color(blue)2/color(red)cancelcolor(black)3(x+8)
color(blue)3*(x+6)=color(blue)2*(x+8)
color(blue)3x+color(blue)3*6=color(blue)2x+color(blue)2*8
color(blue)3x+color(blue)18=color(blue)2x+color(blue)16
Now, subtract 2x from both sides, then 18:
3x+18=2x+16
3x+18color(blue)-color(blue)(2x)=2x+16color(blue)-color(blue)(2x)
3xcolor(blue)-color(blue)(2x)+18=2x-color(blue)(2x)+16
x+18=color(red)cancelcolor(black)(2x-color(blue)(2x))+16
x+18=16
x+18color(blue)-color(blue)18=16color(blue)-color(blue)18
xcolor(red)cancelcolor(black)(+18color(blue)-color(blue)18)=16color(blue)-color(blue)18
x=16-18
x=-2