When the polynomial x^4 + bx^3 + 5x^2 + dx + 6 is divided by x - 2 the remainder is 16. When it is divided by x + 1 the remainder is 10. Find the value of constant d. Date of Exam May 2008 Subject Mathematics, Surveying and Transportation Engineering Problem When the polynomial x4+bx3+5x2+dx+6 is divided by x−2 the remainder is 16. When it is divided by x+1 the remainder is 10. Find the value of constant d. A. 7 C. -5 B. -7 D. 5 Answer Key Click here to show or hide the answer key [ A ] Solution Click here to expand or collapse this section f(x)=x4+bx3+5x2+dx+6 By Remainder Theorem When f(x) is divided by x - 2, the remainder is f(2) f(2)=24+b(23)+5(22)+d(2)+6=16 8b+2d=−26 ← Equation (1) When f(x) is divided by x + 1, the remainder is f(-1) f(−1)=(−1)4+b(−1)3+5(−1)2+d(−1)+6=10 −b−d=−2 ← Equation (2) From Equation (1) and Equation (2) b=−5 d=7 ← answer Category Algebra Remainder Theorem Polynomial in x Log in or register to post comments