When you plug in a value into an expression or equation, you must put what around it?

Can someone me with this problem i don't understand i need

What is the value of x in the following equation? -3x-2=2x+8

Mr. brettler is hanging up a 5-foot tall rectangular welcome sign in the gym. he has drawn a sketch on a coordinate grid. he has the lower vertices of the sign at (9, –3) and (–6, –3). where would the upper vertices be on the grid?