Question
Download Solution PDF"If x² - 5x + 4 is a factor of x⁴ - px² + q, then what are the values of p and q respectively?"
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFGiven:
If x2 - 5x + 4 is a factor of x4 - px2 + q.
Formula used:
If (x2 - 5x + 4) is a factor of (x4 - px2 + q), then the roots of x2 - 5x + 4 (i.e., 1 and 4) must satisfy x4 - px2 + q = 0.
Calculation:
Roots of x2 - 5x + 4 are x = 1 and x = 4.
Substitute x = 1 in x4 - px2 + q = 0
⇒ 14 - p(12) + q = 0
⇒ 1 - p + q = 0
⇒ q = p - 1 ----- (1)
Substitute x = 4 in x4 - px2 + q = 0
⇒ 44 - p(42) + q = 0
⇒ 256 - 16p + q = 0
⇒ q = 16p - 256 ------ (2)
Equate q values from 1 and 2
⇒ p - 1 = 16p - 256
⇒ 255 = 15p
⇒ p = 17
Substitute p = 17 into q = p - 1
⇒ q = 17 - 1
⇒ q = 16
∴ The values of p and q are 17 and 16 respectively.
The correct answer is option (1).
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