The given expression is:
2x^4
- ax^3 -10x^2 + bx - 54
As (x - 2) is a factor of the given
expression:
For x = 2 the value of factor (x - 2) = (2 - 2)
= 0
As one factor is 0 the value of the complete expression
is also zero. Therefor substituting value x = 2 in the given expression and equating it
to 0 we get:
2(2^4) - a(2^3) -10(2^2) + b*2 - 54
=54
32 - 8a - 40 + 2b - 54 =
0
- 8a + 2b = 62 ...
(1)
Similarly:
As (x + 3) is a
factor of the given expression:
For x = -3 the value of
factor (x + 3) = (- 3 + 3) = 0
As one factor is 0 the value
of the complete expression is also 0. Therefore substituting value x = - 3 in the given
expression and equating it to 0 we get:
2(3^4) - a(3^3)
-10(3^2) + b*(-3) - 54 =54
162 + 27a - 90 - 3b - 54 =
0
27a - 3b = - 18
9a - b = -
6 ... (2)
Multiplying equation 2 by 2 we
get:
a + 2b = 62
18a - 2b = -
12 ... (3)
Adding equations (1) and (3) we
get:
- 8a + 18a + 2b - 2b = 62 -
12
10a =
50
Therefore:
a = 50/10 =
5
Substituting this value of a in equation (2) we
get:
9*5 - b = - 6
45 - b = -
6
b = - 6 - 45 = -
51
Answer:
a = 5, and b = -
51
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