[tex]2(x+6)+40=4x\\2x+12+40=4x\\2x+12+40-4x=0\\2x-4x+52=0\\-2x+52=0\\-2x=-52\\x=26[/tex]
Basically multiply the 2 inside the bracket, then addition and subtraction. For the -2x=-52 part. Move -2 to divide the -52, you'll get x = -52/-2 as you'll get x = 26 because minus * minus or minus divide minus will always be positive.
