Answer:
The value of d = -5
The polynomial function x³ +5 x² - 4x -20 =0
Step-by-step explanation:
Explanation
Given that the equation is third degree polynomial
p(x) = x³ - d x² - 4x -20
Given factors x= 2 and x=-2
Substitute 'x' = 2 in given polynomial
8 -d(2²)-4(2) - 20 =0
⇒ 8 - 4 d - 8 -20=0
⇒ - 4 d-20 = 0
⇒ - 4 d = 20
⇒ d = - 5
The value of d = -5
Verification:-
After substitution d =-5 in given polynomial
x³ - (-5) x² - 4x -20 =0
put x=2
8 +5(4)-8-20 =0
20 =20
The factors are x= 2 and x=-2 of the given polynomial
