The cost of equal priced dvds and the number purchased is linear or not?

What is the value of the discriminant of the quadratic equation -2x = -8x + 8 and what does its value mean about thenumber of real number solutions the equation has?

If you have 12 feet of string and you cut it into equal length of 5 inches each how much string will be left

Can someone me and explain..will award brainlest!