1 2 3 4 5 6 7 8 9 10 Time Remaining 59:13 The image of a parabolic lens is traced onto a graph. The function f(x) = (x + 8)(x – 4) represents the image. At which points does the image cross the x-axis? (–8, 0) and (4, 0) (8, 0) and (–4, 0) (2, 0) and (–1, 0) (–2, 0) and (1, 0) Mark this and return Save and Exit Next Submit

Respuesta :

If you are given an image of a parabolic lens, then apply the formula (y - h)² = 4a(x - k) or (x - h)² = 4a(y - k). You are given the function f(x) = (x + 8)(x – 4) and you are asked to find which points does the image cross the x-axis. To solve this, yo need to expand the given equation. 

f(x) = (x + 8)(x – 4)
y = (x + 8)(x – 4)
y = x² - 4x + 8x - 36
y = x² + 4x - 32
From the equation that we derived, we can see that the parabola is facing rightward the x - axis. Among the choices, (–8, 0) and (4, 0) crosses the x-axis.