2x+5x=4x+12
7x=4x+12
7x-4x=12
3x=12
x=12:3
x=4
2x+5x=4x+12
7x=4x+12
7x-4x=12
3x=12
x=12:3
x=4
2x-[-5x]=4[x+3]
=>2x+5x=4x+12
=>7x=4x+12
=>7x-4x=12
=>3x=12
=>x=4
2x-[-5x]=4[x+3]
=>2x+5x=4x+12
=>7x=4x+12
=>7x-4x=12
=>3x=12
=>x=4
2x+5x=4x+12
7x=4x+12
7x-4x=12
3x=12
x=12:3
x=4