Question

tim x : x² -5x+4=0

x²+x-6=0

Answer 1

b/ x² + x + 6 = 0 

=> x² + 2.1/2 .x + (1/4) - (1/4) + 6 = 0

=> (x + 1/2)² + 23/4 = 0 

mà (x + 1/2)2 + 23/4 > 0 => vô nghiệm

Answer 2

a,x²​-5x+4=0

 x^2-x-4x+4=0

(x^2-x)-(4x-4)=0

x(x-1)-4(x-1)=0

(x-1)(x-4)=0

x-1=0.                                 x-4=0

x=1                                       x=4