Question 1183399
if {{{f(x) = ax^3 + bx^2 + 2x + 3}}}, then by the remainder theorem, the remainder upon division of {{{f(x)}}} by {{{x-1}}} is equal to {{{f(1) = a+b+2+3 = a+b+5}}}.

Similarly, the remainder upon division of {{{f(x)}}} by {{{x+1}}} is equal to {{{f(-1) = -a+b-2+3 = -a+b+1}}}.

From the given, {{{f(1) = 2f(-1)}}}, hence

{{{a+b+5 = 2(-a+b+1) = -2a+2b+2}}} ==> {{{highlight(3a + 3 = b)}}}.