Question

if (x+1) and (x+2) are factors of ax^3+x^2-2x+b find a and b

Answer 1

x+2 = 0. ; x+1 = 0

x = -2 ; x = -1

Put x= -1, -2 to find a and b

First,put x = -2

ax³+x²-2x+b = 0

a(-2)³+(-2)²-2(-2)+b=0

a-8+4+4+b=0

a+b-1 = 0

a+b = 1 --------(1)

Put x = -1

a(-1)³+(-1)²-2(-1)+b = 0

a(-1)+1+2+b = 0

-a+b+3 = 0

-a+b = -3 -------(2)

(1)+(2)

a+b = 1

-a+b=-3

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2b = -2

b = -2/2

b = -1

Put b= -1 in (1)

a+(-1) = 1

a-1 = 1

a=1+1

a=2

Therefore, a = 2 and b = -1

Answer 2

Answer:

Step-by-step explanation: