left parenthesis 6.9 c plus 8 right parenthesis plus left parenthesis 8.28 x minus 4 right parenthesis plus left parenthesis 7.2 n plus 2 right parenthesis(6.9c+8)+(8.28x−4)+(7.2n+2)equals= enter your response here ​(Simplify your answer. Use integers or decimals for any numbers in the​ expression.)