x^2-5x+4=0
x.x-5.x+4=0
x.x-5.x=-4
=>x=1
tk minh nha
\(\Rightarrow x\in\left\{1;4\right\}\)
tk ủng hộ nha
x2-5x+4=0
<=>x2-x-4x+4=0
<=>(x2-x)+(-4x+4)=0
<=>x(x-1)+4(-x+1)=0
<=>x(x-1)-4(x-1)=0
<=>(x-1)(x-4)=0
<=>x-1=0 hay x-4=0
<=>x=1 x=4
x2-5x+4=0
<=>x2-x-4x+4=0
<=>x(x-1)-4(x-1)=0
<=>(x-4)(x-1)=0
<=>x-4=0 hoặc x-1=0
<=>x=4 hoặc x=1
vậy x=4 hoặc x=1
x^2-5x+4=0
x.x-5.x+4=0
x.x-5x =0-4
x.x-5.x =-4
rút gọn vế trái : [X.x-X.5]=x-5=-4
x=-4+5
x=1
x2 - 5x + 4 = 0
<=> x2 - x - 4x + 4 = 0
<=> x ( x - 1 ) - 4 ( x- 1 ) = 0
<=> ( x - 4 ) ( x - 1) = 0
<=> x - 4 =0
x - 1 = 0
<=> x = 4
x = 1
Vậy S = { 4 ; 1 }