ANSWER
No real roots.
The roots are complex or imaginary.
EXPLANATION
The quadratic equation
has discriminant,
If the discriminant is less than zero , then the quadratic equation has no real roots.
The given discriminant is -9.
Since -9 is less than zero, it means the quadratic equation has complex or imaginary roots.
Answer:
Time taken by Doreen is 6 hours and speed is 10 miles per hour.
Time taken by Sue is 4 hours and speed is 20 miles per hour.
Step-by-step explanation:
Let the speed of Doreen be x
According to the question speed of Sue is = x+10
time taken By Sue to cover 80 miles =
time taken by Doreen to travel 60 miles =
According to question Sue take two hours less than Doreen takes
therefore
-
=2
=2
60(x+10) -80x = 2(x(x+10)
60x+600-80x =
simplifying it ,we get
Dividing both sides by 2 ,we get
solving it for x ,we get
(x+30)(x-10) =0
x =-30 which is not possible
x =10 miles per hour
Speed of Doreen = 10 miles per hour
Speed of Sue = 10+10 = 20 miles per hour
Time taken by Doreen = 60 divided by 10 = 6 hours
Time taken by Sue = 80 divided by 20 = 4 hours