Respuesta :

Answer:

Step-by-step explanation:

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Answer:x=-2 or x=20

Step-by-step explanation:

X^2-18x-40=0

X^2+2x-20x-40=0

X(x+2)-20(x+2)=0

(X+2)(x-20)=0

X+2=0 or x-20=0

X=-2 or x=20