Do discriminates have 1 or 2 answers

i want to say 2 but it my be 1

Step-by-step explanation:

If it is more than 0, the equation has two real solutions. If it's less than 0, there are no solutions. If it's equal to 0, there is one solution.

The interest rate would be 2.4%.

We start out finding the total amount he pays, including interest. 

78.40/month * 12 months * 5 years = $4704

We take off the amount of principal:
4704-4200 = 504

This is the amount of interest he pays.  Now we use the simple interest formula, I=prt:

504=4200(r)(5)

Multiply 4200 and 5:
504=21000r

Divide both sides by 21000:
504/21000 = 21000r/21000
0.024 = r
2.4% = r