Respuesta :

Louli
Answer:
either x = 5 or x = -1 (second option)

Explanation:
We are asked to use the u substitution. This means that we will assume that:
u = x - 3

Substitute in the given expression:
u^2 + 2u - 8 = 0
(u-2)(u+4) = 0
either u = 2
or u = -4

Now, we have:
u = x- 3
at u = 2: 
x - 3 = 2
x = 2 + 3 = 5

at u = -4:
x - 3 = -4
x = -4 + 3 = -1

Hope this helps :)
carlosego
(x-3) ^ 2 + 2 (x-3) -8 = 0
 Using substitution we have:
 u = x-3
 We rewrite:
 (u) ^ 2 + 2 (u) -8 = 0
 We are looking for roots:
 u1 = 2
 u2 = -4
 We return the change:
 u1 = 2 = x-3
 x1 = 3 + 2 = 5
 u2 = -4 = x-3
 x2 = -4 + 3 = -1
 Answer:
 x1 = 5
 x2 = -1
 (option2)

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