3x+2{45-x-3[3x+7]-2x}+4x=55
<=>3x+2[45-x-9x-27-2x]+4x=55
<=>3x+90-2x-18x-54-4x+4x=55
<=>36-17x=55
<=>17x=-19
<=>x=-19/17
Vậy x=-19/17
3x+2{45-x-3[3x+7]-2x}+4x=55
=> 7x+2{45-x-9x-21-2x}=55
=>7x+2{24-12x}=55
=>7x+48-24x=55
=>-17x=7
=> x=\(\frac{-7}{17}\)
3x + 2{45-x-9x -21 - 2x } + 4x = 55
suy ra 3x + 2{24-12x}+4x=55
suy ra 3x + 48 - 24x + 4x = 55
suy ra 17x=-7
suy ra x=-7/17
3x+2{45-x-3[3x+7]-2x}+4x=55
3x+2[45-x-9x+21-2x}+4x=55
7x+90-2x-18x+42-4x=55
(7x-2x-18x-4x)+90+42=55
-17x+90=13
-17x=-77
x=-77/-17
3x+2{45-x-3[3x+7]-2x}+4x=55
3x+2[45-x-9x-27-2x]+4x=55
3x+90-2x-18x-54-4x+4x=55
36-17x=55
17x=-19
x=-19/17
Vậy x=-19/17
3x + 2{45-x-9x -21 - 2x } + 4x = 55
=>3x + 2{24-12x}+4x=55
=> 3x + 48 - 24x + 4x = 55
=> 17x=-7
=> x=-7/17
Vậy x=7/17
Hok tốt !!!
Vậy x=-7/17 nha mn. Sorry mn nhiều !!!
thank you everyone