How do you solve #4x ^ { 2} - 24= 2x ( x + 4)#?

1 Answer
Nghi N
Jul 14, 2017

-2; 6

Explanation:

#4x^2 - 24 = 2x(x + 4)#
#4x^2 - 24 = 2x^2 + 8x#
#2x^2 - 8x - 24 = 2(x^2 - 4x - 12) = 0#
Find 2 real roots knowing the sum (-b = 4) and the product (c = - 12).
They are: -2 and 6.

Note . Once you find the 2 numbers (2, -6), the opposite numbers (- 2, 6) are the 2 real roots. It isn't needed to go further in factoring by grouping and solving the 2 binomials.

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