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A polynomial p(x) = x⁴-2x³+3x²-ax+b, when divided by x-1 gives remainder as 5, when divided by x+1 gives remainder 19. Will this polynomial p(x) be multiple ofx-2? Support your answer with suitable working. |
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Answer»
answer: hope it works
explanation : When f(x) is DIVIDED by x-1 and x+1 the remainder are 5 and 19 respectively.∴f(1)=5 and f(−1)=19⇒(1)4−2×(1)3+3×(1)2−a×1+b=5and (−1)4−2×(−1)3+3×(−1)2−a×(−1)+b=19⇒1−2+3−a+b=5and 1+2+3+a+b=19⇒2−a+b=5 and 6+a+b=19⇒−a+b=3 and a+b=13Adding these two EQUATIONS, we get(−a+b)+(a+b)=3+13⇒2b=16⇒b=8Putting b=8 and −a+b=3, we get−a+8=3⇒a=−5⇒a=5Putting the values of a and b inf(x)=x4−2x3+3x2−5x+8The remainder when f(x) is divided by (x-2) is equal to f(2).So, Remainder =f(2)=(2)4−2×(2)3+3×(2)2−5×2+8=16−16+12−10+8=10 |
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