Question

(x – 4)(x + 10) = -17

Answer 1

Answer:

-3 +   4sqrt(2)

-3  -  4sqrt(2)

Step-by-step explanation:

(x – 4)(x + 10) = -17

FOIL on the left hand side  (First outer inner last)

x^2 +10x-4x-40 = -17

x^2 +6x-40 =-17

Add 17 to each side

x^2 +6x-40+17 =-17+17

x^2 +6x -23 = 0

Using the quadratic formula

-b + - sqrt(b^2 -4ac)

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   2a        

where ax^2 +bx+c=0

-6 + - sqrt(6^2 -4*1*-23)

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   2*1

-6 + - sqrt(36 +92)

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   2

-6 + - sqrt(128)

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   2

-6 + -  8sqrt(2)

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   2

Divide top and bottom by 2

-3 + -  4sqrt(2)