Question

Find the value of a and b if x-1 and x-2 is the factor of x^3-ax+b

Answer 1

Answer:

Step-by-step explanation:

x-1=0

x=1

x-2=0

x=2

f(x)=x³-ax+b=0

since x-1 is a factor

f(1)=0

1³-a*1+b=0

1-a+b=0

a-b=1  ............................(1)

Now since x-2 is a factor

f(2)=0

2³-a*2+b=0

8-2a+b=0

2a-b=8   ................(2)

Solving (1)&(2)

2a-b-a+b=8-1

a=7

2a-b=8

2*7-b=8

b=14-8

   =6

Hope it helps!!!!