a, \(\left(2600+6400\right)-3x=1200\)
\(\Rightarrow9000-3x=1200\)
\(\Rightarrow3x=7800\)
\(\Rightarrow x=2600\)
b, \(\left[\left(6x-72\right):2-84\right].28=5628\)
\(\Rightarrow\left(6x-72\right):2-84=201\)
\(\Rightarrow\left(6x-72\right):2=285\)
\(\Rightarrow6x-72=570\)
\(\Rightarrow6x=642\)
\(\Rightarrow x=107\)
a) (2600 + 6400) - 3x = 1200
9000 - 3x = 1200
3x = 9000 - 1200
3x = 7800
x = 2600
Vậy x = 2600
b) [(6x - 72) : 2 - 48].28 = 5628
(6x - 72) : 2 - 48 = 5628 : 28
(6x - 72) : 2 - 48 = 201
(6x - 72) : 2 = 201 + 48
(6x - 72) : 2 = 249
6x - 72 = 249.2
6x - 72 = 498
6x = 498 + 72
6x = 570
x = 570 : 6
x = 95
Vậy x = 95
a,(2600+6400)-3.x=1200
=>9000-3.x=1200
=> 3.x=9000-1200
=> 3.x=7800
=> x=7800:3
=> x=2600
vậy x=2600
b,[(6.x-72):2-84].28=5628
=>(6.x-72):2-84 =5628:28
=>(6.x-72):2-84 =201
=>(6.x-72):2 =201+84
=>(6.x-72):2 =285
=>6.x-72 =285.2
=>6.x-72 =570
=>6.x =570+72
=>6.x =642
=> x =642:6
=> x =107
vậy x =107
