Question 1037635
This is mostly about substitutions and doing simple arithmetic of functions.  


Only doing the last part of the question,
{{{r(x)*s(x)=r*s(x)}}}
{{{(2x+6)(3x)}}}
{{{6x^2+18x}}}
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Let x=-1.
{{{6(-1)^2+18(-1)}}}
{{{6-18}}}
{{{highlight(-12)}}}