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Question-96904




Question Number 96904 by pticantor last updated on 05/Jun/20
Commented by pticantor last updated on 05/Jun/20
 show that there are 4 real numbers a,b,c and d           which will be specified such that  (x^2 −4x+5)^2 +(x+1)^2 =(x^2 +ax+b)(x^2 +cx+d)
$$\:\boldsymbol{{show}}\:\boldsymbol{{that}}\:\boldsymbol{{there}}\:\boldsymbol{{are}}\:\mathrm{4}\:\boldsymbol{{real}}\:\boldsymbol{{numbers}}\:\boldsymbol{{a}},\boldsymbol{{b}},\boldsymbol{{c}}\:\boldsymbol{{and}}\:\boldsymbol{{d}}\:\:\:\:\:\:\:\:\: \\ $$$$\boldsymbol{{which}}\:\boldsymbol{{will}}\:\boldsymbol{{be}}\:\boldsymbol{{specified}}\:\boldsymbol{{such}}\:\boldsymbol{{that}} \\ $$$$\left(\boldsymbol{{x}}^{\mathrm{2}} −\mathrm{4}\boldsymbol{{x}}+\mathrm{5}\right)^{\mathrm{2}} +\left(\boldsymbol{{x}}+\mathrm{1}\right)^{\mathrm{2}} =\left(\boldsymbol{{x}}^{\mathrm{2}} +\boldsymbol{{ax}}+\boldsymbol{{b}}\right)\left(\boldsymbol{{x}}^{\mathrm{2}} +\boldsymbol{{cx}}+\boldsymbol{{d}}\right) \\ $$
Commented by john santu last updated on 05/Jun/20
⇒x^4 −8x^3 +27x^2 −38x+26 =   (x^2 −2x+2)(x^2 −6x+13)    { ((a=−2, b = 2 , c = −6 , d = 13 or)),((a=−6, b = 13 , c = −2 , d = 2)) :}
$$\Rightarrow{x}^{\mathrm{4}} −\mathrm{8}{x}^{\mathrm{3}} +\mathrm{27}{x}^{\mathrm{2}} −\mathrm{38}{x}+\mathrm{26}\:=\: \\ $$$$\left({x}^{\mathrm{2}} −\mathrm{2}{x}+\mathrm{2}\right)\left({x}^{\mathrm{2}} −\mathrm{6}{x}+\mathrm{13}\right)\: \\ $$$$\begin{cases}{{a}=−\mathrm{2},\:{b}\:=\:\mathrm{2}\:,\:{c}\:=\:−\mathrm{6}\:,\:{d}\:=\:\mathrm{13}\:{or}}\\{{a}=−\mathrm{6},\:{b}\:=\:\mathrm{13}\:,\:{c}\:=\:−\mathrm{2}\:,\:{d}\:=\:\mathrm{2}}\end{cases} \\ $$
Commented by pticantor last updated on 05/Jun/20
thank you sir
$$\boldsymbol{{thank}}\:\boldsymbol{{you}}\:\boldsymbol{{sir}} \\ $$

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