a)
[tex] {x}^{2} - 5x + 4 = \\ = {x}^{2} - 4x - x + 4 = \\ = x(x - 4) - (x - 4) = \\ = (x - 4)(x - 1)[/tex]
x - 4 = 0
x1= 4
sau
x - 1 = 0
x2= 1
x={1;4}
b)
[tex] {x}^{2} - 4x + 4 = \\ = {x}^{2} - 2x - 2x + 4 = \\ = x(x - 2) - 2(x - 2) = \\ = (x - 2)( x - 2) = \\ =(x - 2) {}^{2} [/tex]
x-2=0
x=2
…ᘛ⁐̤ᕐᐷฅ^•ﻌ•^ฅฅ^•ﻌ•^ฅ
