ai giúp mình với

Move everything to make it a quadratic equaation:

x^2-4x=5

x^2-4x-5=0

 

Factor and solve for x:

(x-5)(x+1)=0

x=5, -1

Change it into a polynomial: 

x^2-4x-5=0

Simplify from there by factoring:

(x-5)(x+1)=0

x = 5, -1