Question

3. If (x - 1) and (x - 2) are two factors of x3 - ax2 + 14x + b; the values of a and
bare
(a) a = 6, b = 7
(b) a = -8, b = -7
() a = 7, b = -8
(d) a = 7,5 = 8
[Ans. a = 7, b = -8]​

Answer 1

Step-by-step explanation:

on putting the value of x-1=0 in the above equation

1-a+14+b=0

b-a=-15........(1)

on putting the value of x-2=0 in the above equation

8-4a+28+b=0

b-4a=-36 .......(2)

on subtracting eq1 and eq2.

b-a=-15

b-4a=-36

- + +

3a=21

a=7

on putting the value of a in eq1

b-7=-15

b=-8