a) 4x - 10 = 0
<=> 4x = 10
<=> x = $\frac{5}{2}$
Vậy x = $\frac{5}{2}$
b) 7 - 3x = 9 - x
<=> -3x + x = 9 - 7
<=> -2x = 2
<=> x = -1
Vậy x = -1
c) 2x - (3 - 5x) = 4(x + 3)
<=> 2x - 3 + 5x = 4x + 12
<=> 2x + 5x - 4x = 12 + 3
<=> 3x = 15
<=> x = 5
Vậy x = 5
d) 5 - (6 - x) = 4(3 - 2x)
<=> 5 - 6 + x = 12 - 8x
<=> x + 8x = 12 - 5 + 6
<=> 9x = 13
<=> x = $\frac{13}{9}$
Vậy x = $\frac{13}{9}$