Danho

Paper 2 · June 2017 · Algebraic manipulation

Express 3x2+6x+7x2+2x+1\dfrac{3x^{2}+6x+7}{x^{2}+2x+1} in the form A(x+B)2+C\dfrac{\mathrm{A}}{(x+\mathrm{B})^{2}}+\mathrm{C}, stating the values of the constants A, B and C.

Model answer

A=4\mathrm{A}=4, B=1\mathrm{B}=1, C=3\mathrm{C}=3

Also accepted: A=4, B=1, C=3, 4, 1, 3, A=4 B=1 C=3

Explanation

The denominator factorises as x2+2x+1=(x+1)2x^{2}+2x+1=(x+1)^{2}, and the numerator can be written 3(x2+2x+1)+4=3(x+1)2+43(x^{2}+2x+1)+4=3(x+1)^{2}+4. Dividing, 3(x+1)2+4(x+1)2=4(x+1)2+3\dfrac{3(x+1)^{2}+4}{(x+1)^{2}}=\dfrac{4}{(x+1)^{2}}+3, so A=4\mathrm{A}=4, B=1\mathrm{B}=1 and C=3\mathrm{C}=3.

Derived from ZIMSEC Mathematics Paper 2, June 2017, Q1

View this paper's sittings and topics→

More questions from this paper

Get the full paper, not just one question

Danho has every sitting for this paper, with your progress tracked question by question, offline.