Question 1024461
Since one of the roots is complex and it has real coefficients, the complex conjugate is also a root.
{{{f(x)=a(x+2)(x-(5+4i))(x-(5-4i))}}}
{{{f(x)=a(x+2)(x^2-10x+41)}}}
When {{{x=-1}}}
{{{f(-1)=a(-1+2)(-1^2+10+41)}}}
{{{52=a(1)(52)}}}
{{{a=1}}}
So then,
{{{f(x)=(x+2)(x^2-10x+41)}}}
{{{f(x)=x^3-8x^2+21x+82}}}
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*[illustration gxc1.JPG].