Hi there, having trouble with these three here. Thanks for any help.
1. Factor the expression using the four train cars strategy from class: x^3+6x^2-25x-150
Show your work.
Answer: The first step is:
p2 + 16p + ____ = 17 + ____
Answer:
+128408 1. Don't really know what the four train car stategy is....but....
x^3 +6x^2 - 25 x - 150 =
(x^2) ( x + 6) - (25)(x + 6) =
(x^2 - 25) ( x + 6) =
(x + 5) ( x - 5) ( x + 6)
2. p^2 + 16p = 17
Take 1/2 of 16 = 8
Square it = 64
Add to both sides
p^2 + 16p + 64 = 17 + 64
Factor the left side....simplify the right
(p + 8)^2 = 81
Take both roots
p + 8 = sqrt (81) p + 8 = -sqrt (81)
p + 8 = 9 p + 8 = -9
p = 9 - 8 p = -9 -8
p = 1 p = -17
3)
(a^2 + 4a – 1) (7a - 2) =
a^2 * 7a - 2a^2 + 4a*7a + 4a(-2) - 1(7a) -1(-2) =
7a^3 - 2a^2 + 28a^2 - 8a - 7a + 2 =
7a^3 + 26a^2 - 15a + 2
