J's answer to Tammy Chan's Hong Kong question.
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(2x + k)(x + 6) = x² - 36
(2x + k)(x + 6) = x² - 6²
(2x + k)(x + 6) = (x - 6)(x + 6)
(Recall the property (a+b)(a-b) = a² - b²)
(2x + k)(x + 6) - (x - 6)(x + 6) = 0
(2x + k - (x - 6))(x + 6) = 0
(2x + k - x + 6)(x + 6) = 0
(x + k + 6)(x + 6) = 0
x + k + 6 = 0 or x + 6 = 0
x = -k - 6 or x = -6
Next part : (2x - 3)(x + 6) = 0 can bd rewritten as (2x + (-3))(x + 6) = 0
So all we have to do, is to replace k with -3 in our previous solution.
x = -(-3) - 6 or x = -6
x = -3 or x = -6
(2x + k)(x + 6) = x² - 6²
(2x + k)(x + 6) = (x - 6)(x + 6)
(Recall the property (a+b)(a-b) = a² - b²)
(2x + k)(x + 6) - (x - 6)(x + 6) = 0
(2x + k - (x - 6))(x + 6) = 0
(2x + k - x + 6)(x + 6) = 0
(x + k + 6)(x + 6) = 0
x + k + 6 = 0 or x + 6 = 0
x = -k - 6 or x = -6
Next part : (2x - 3)(x + 6) = 0 can bd rewritten as (2x + (-3))(x + 6) = 0
So all we have to do, is to replace k with -3 in our previous solution.
x = -(-3) - 6 or x = -6
x = -3 or x = -6
Date Posted:
3 years ago
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