In the equation y = 2x2 - 6x - 8, which of the following is a value of x when y = 0?

Question

In the equation y = 2x2 - 6x - 8, which of the following is a
value of x when y = 0?

Answer 1

y = 2x² - 6x - 8 = 2(x² - 3x - 4) = 2(x - 4)(x + 1) = 0 ⇒

 

x - 4 = 0 or x + 1 = 0 ⇒

 

x = 4 or -1

 

Now try to find these 2 values of x in your list of candidates, which you did not include in the problem statement.