When divided by x - 1, the polynomial P(x) = x5 + 2x3 +Ax + B, where A and B are constants, the remainder is equal to 2. When P(x) is divided by x + 3, the remainder is equal -314. Find A and B.
Answers
ANSWER :–
A = 4 and B = -5
EXPLANATION :–
GIVEN :–
• A Polynomial P(x) = x⁵ + 2x³ + Ax + B, where A and B are constants.
• When polynomial divided by x - 1 , the remainder is 2 .
• When polynomial divided by x + 3 , the remainder is -314
TO FIND :–
Values of A and B .
SOLUTION :–
• If polynomial is divided by x - 1 then x = 1 will satisfy the equation –
=> p(1) = 2
=> (1)⁵ + 2(1)³ + A(1) + B = 2
=> 1 + 2 + A + B = 2
=> A + B = -1 ————————eq.(1)
• Now p(x) is divided by x + 3 then –
=> p(-3) = -314
=> (-3)⁵ + 2(-3)³ + A(-3) + B = -314
=> -243 - 54 - 3A + B = -314
=> -297 - 3A + B = -314
=> -3A + B = -314 + 297
=> -3A + B = -17 ––——–————eq.(2)
• Now subtract eq.(1) by eq.(2) –
=> A + B - ( -3A + B ) = - 1 - (- 17)
=> 4A = 16
=> A = 4
• Put the value of 'A' in eq.(1) –
=> 4 + B = -1
=> B = -5
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