Question

(x-1)(x+5)=20

Answer 1

`(x-1)(x+5) = 20`

`=>x^2 + 4x - 5 - 20 = 0`

`=> x^2 + 4x -25 = 0`

`=> x^2 + 4x + 4 - 29 = 0`

`=> (x + 2)^2 = 29`

TH1 : 

\(x+2=\sqrt{29}\)

`=>` \(x=\sqrt{29}-2\)

TH2:

\(x+2=-\sqrt{29}\)

`=>`\(x=-\sqrt{29}-2\)

Vậy .... 

Answer 2

tìm x

Answer 3

29

Answer 4

TH1:(x-1)=20

x-1=20

x=20+1

x=21

TH2:(x+5)=20

x+5=20

x=20-5

x=15

vậy x1=21 và x2=15