How do you find the x and y intercept of #-16x^2+24x-5#?

1 Answer
Jul 17, 2015

Answer:

Solve #y = - 16x^2 + 24x - 5.#
Answers: 1/4 and 5/4

Explanation:

To find y-intercept, make x = 0 --> y = - 5
To find x-intercepts, solve #y = - (16x^2 - 24x + 5) = 0 (1)#
I use the new Transforming Method (Google, Yahoo Search).
Transformed equation: #y' = x^2 - 24x + 80.(2)# Roots have same sign.
Factor pairs of (80) -->...(2, 40)(4, 20). This sum is 24 = -b. Then the 2 real roots are: y1 = 4 and y2 = 20.
Back to original equation (1), the 2 real roots are: #x1 = (y1)/a = 4/16 = 1/4# and #x2 = (y2)/a = 20/16 = 5/4#