151k views
3 votes
Number 53

Find the x-intercepts of y = 4x2 - 15x - 4.
4 and 1/4
-21 and 10
-1/4 and 4
No x-intercepts exist.

User Xhadon
by
8.0k points

1 Answer

7 votes
x-intercepts
f(x) = 0

4x² - 15x - 4 = 0

4x² - 16x + x - 4 = 0

4x(x - 4) + 1(x - 4) = 0

(x - 4)(4x + 1) = 0 ⇔ x - 4 = 0 or 4x + 1 = 0

x = 4 or 4x = - 1 ⇒ x = - 1/4

Answer: -1/4 and 4.
User Charanjit Singh
by
7.2k points