Answer:
3.5 or -1 first of all know the formula method , I Don't have the right symbols so I don't want to confuse you so the number infront of x^2 or any alphabet with a square is a , b is the number infront of the letter without a square and c is the single number without an alphabet, this is the easiest formula compared to factorization method so check online or your textbook for the formula
