Please help math question

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

Iwas absent when my class learned this and my teacher is to lazy to teach it to me explain this to me .

Agame store sells  2  large puzzles for  $16  and  3 small puzzles for  $15.  the store made  $128  in puzzle sales this week.the equation  8l+5s=128  represents this week's earnings from puzzle sales, where  ll  represents the number of large puzzles sold and  s  represents the number of small puzzles sold.which statements are correct regarding the equation  8l+5s=128? select all the apply.1.the coefficient 5 in the equation gives the cost of one large puzzle.2.the coefficient 5 in the equation gives the cost of one small puzzle.3.the constant 128 in the equation gives the total number of puzzles sold.4.the coefficient 8 in the equation gives the cost of one large puzzle.5.the coefficient 8 in the equation gives the cost of one small puzzle.