Question

if x 3 is a factor of x 3 ax 2x^3+ax^2+2bx+18 and a+b=−7 find a and b

Answer 1

Answer:

f(x)=x³+ax²+2bx-24

f(4)=4³+a.4²+2.b.4-24=0

=>64+16a+8b=24

=> 16a+8b=24-64

=> 2a+1b=3-8

=> 2a+b=-5.........(i)

a-b=8..........(ii)

Solving eq.(i) & (ii)

2a+b=-5

a-b=8

_________

3a=3

=>a=1

Substituting the value of a in eq.(ii)

1-b=8

=>b=-7

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Answer 2

Answer:

b=-7 is your answer.........