Question

If x=0 and x=(-1) are the roots of the polynomial f(x) =2x^3-3x^2+ax+b,find value of a and b

Answer 1

1). when x =0 , f(x) = 0

so, 0+0+0+b = 0

so, b = 0

2). when x= -1 , f(x) = 0

so, 2 * (-1)^3 - 3 * (-1)^2 - a = 0

so, -2 -3 -a = 0

so, a = -5

hence, a = -5 and b = 0

Answer 2

Answer:

a = -5      b = 0

Step-by-step explanation:

f ( x ) = 2x^3 - 3x^2 + ax + b

f ( 0 ) = 2( 0 ) ^3  -  3( 0 )^2  +  a ( 0 )  + b

0 = 0  -  0  +  0  + b

b = 0

f ( -1 ) = 2 (-1) ^3 - 3 ( -1 )^2 + a ( -1 ) + b

0 = 2 (-1)  - 3 ( 1 ) - a  + 0      ( ∵  b = 0 )

0 = -2   - 3  - a  

a = -5

∴  a = -5      b = 0