For this case we have that by definition, the discriminant of a quadratic expression is given by:
If the discriminant is less than zero then the expression has two different complex roots.
In this case we have the following expression:
So we have to:
The discriminant is given by:
Then, if we want two complex roots it must be fulfilled that:
Thus, the expression has two complex roots for all values greater than 4.
ANswer:
Answer:
7 mins
Step-by-step explanation:
Current speed of Joes Car = 65.5 mph
We have to find the time interval for which the car exceeded the speed limit of 55 mph.
While, we are given that the speed of the car was constantly increasing, hence the speed over all increased from the limit of 55 mph = 65.50-55.00 = 10.50 mph
We are also given that Joes car was increasing speed at a constant rate of 1.50 mph for every passing minute. Hence
1.50 mph is increased in 1 minute
1 mph will be increase in minutes
Hence
10.50 mph will be increased in minutes
Hence joes car was exceeding the limit of 55 mph for 7 minutes.