Question

What are the coordinates of the x-intercepts of the graph of y = 2x2 + 6x – 20? A) (–5, 0) , (2, 0) . B) (5, 0) , (–2, 0) . C) (–4, 0) , (10, 0) . D) (4, 0) , (–10, 0)

Answer 1

Y = 2 x² + 6 x - 20 = 2 ( x² + 3 x - 10 ) = 2 ( x² + 5 x - 2 x - 10 ) =
= 2 ( x ( x + 5 ) - 2 ( x + 5 ) ) = 2 ( x + 5 ) ( x - 2 )
x 1  = - 5,  x 2  = 2
Answer: A ) ( - 5, 0 ), ( 2, 0 )