Use the grouping method to factor 4x^3 +20x^2-3x-15
a) (x-5)(4x^2+3)
b)(x+5)(4x^2-3)
c)2x(x+1)(2x-15)
d)(x^2-5)(4x+3)

b)  (x + 5)(4x^2 - 3).

Step-by-step explanation:

4x^3 + 20x^2 - 3x - 15

= 4x^2(x + 5) - 3(x + 5)

= (x + 5)(4x^2 - 3).

the answer is 15% decrease

walter needs to make at least 5 more cookies but no more than 40. 5 ≥ x ≥ 40;

step-by-step explanation:

walter has to make a minimum of 20 cookies. he already has 15 cookies made, so he must make 5 more to meet the minimum.

the maximum amount of cookies he can make is 55. he already has 15, so he has to make no more than 40 more cookies to meet the maximum.