a, (x - 1) + (2x + 10 ) = 0
=> x - 1 + 2x + 10 = 0
=> ( x + 2x ) - ( 1 - 10 ) = 0
=> 3x + 9 = 0
=> 3x = -9
=> x = -9 : 3
=> x = -3
b, 2x.(x - 5) +3.(x-5) = 0
=> ( 2x + 3).(x - 5) = 0
=> 2x + 3 =0 hoặc x - 5 = 0
=> 2x = -3 x = 5
=> x = \(\frac{-3}{2}\) x = 5
c, 4x.( x - 3) - 5x + 15 =0
=> 4x .(x - 3) - 5.(x -3 ) = 0
=> ( 4x - 5).(x - 3) =0
=> 4x - 5 = 0 hoặc x - 3 = 0
=> 4x = 5 x = 3
=> x = \(\frac{5}{4}\) x = 3
d, \(x^2-x-3\left(x-1\right)=0\)
=> x.(x - 1) - 3.(x - 1) = 0
=> (x - 3). (x -1 ) = 0
=> x - 3 = 0 hoặc x - 1 = 0
=> x = 3 x = 1
e, \(x^2-9x=0\)
=> x.(x - 9) = 0
=> x = 0 hoặc x - 9 =0
=> x = 0 x = 9
