It means 4 times (3+4) = 28
-2( 3m + 9 ) =
Combine like terms to give 3n + 2
5+6+36-4=43 * * * * * That is an equation, not an expression. An expression might be 5+6+36-4 or 43 but when you put the + sign (or <, > etc) it becomes an equation (or inequality).
aa+2 is an expression, not an equation. An expression has no answer.
Expression
an expression
its 45
41
Yes.
2!
4
The variable is d, in the algebraic expression 7d+2