Question

do this quickly!!!! for 9 points

Answer 1

Given=x³+2x²+ax+b=f(x)
1st factor=x+1
x=-1
f(-1)=-1+2-a+b
      =-a+b+1  (1)
2nd factor=x-1
x=1
f(1)=a+b+3  (2)

Solving (1) and (2), we get,

∴a=-1 and b=-2

Answer 2

x³ +2x² + ax + b is a polynomial equation . which two factors are ( x -1) and ( x +1)

it means it's two roots are 1 , -1
so,
put x = 1
(1)³ +2(1)² +a(1) + b =0

a + b = -3 ------------(1)

put x = -1

(-1)³ +2(-1)² +a(-1) + b =0

b - a +1 =0

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

solve equations (1) and (2)
a = -1 and b = -2