Question 1206405
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Basic algebraic operations....<br>
{{{S+T=(n+5)+(-m-3n+8)}}}
{{{S+T=(-m)+(n-3n)+(5+8)}}}  <-- write the expression with variables first, in alphabetical order
{{{S+T=-m-2n+13}}}  <-- combine like terms<br>
{{{R-(S+T)=(11-2m)-(-m-2n+13)}}}
{{{R-(S+T)=(-2m+11)+(m+2n-13)}}}  <-- subtraction is addition of the opposite
{{{R-(S+T)=(-2m+m)+(2n)+(11-13)}}}
{{{R-(S+T)=-m+2n-2}}}<br>