The answer to the question is c
a = 4, b = -21, c = -18
to keep from getting "mixed up", evaluate the discriminant first ...
b<sup>2</sup> - 4ac = (-21)<sup>2</sup> - 4(4)(-18) = 729
sqrt(729) = 27
x = (21 +/- 27)/8
x = -3/4, x = 6
since the discriminant is a perfect square, the original quadratic will factor ...
4x<sup>2</sup> - 21x - 18 = 0
(4x + 3)(x - 6) = 0
x = -3/4, x = 6
<h2>
Answer:</h2>
a)
The probability that both televisions work is: 0.42
b)
The probability at least one of the two televisions does not work is:
0.5833
<h2>
Step-by-step explanation:</h2>
There are a total of 9 televisions.
It is given that:
Three of the televisions are defective.
This means that the number of televisions which are non-defective are:
9-3=6
a)
The probability that both televisions work is calculated by:

( Since 6 televisions are in working conditions and out of these 6 2 are to be selected.
and the total outcome is the selection of 2 televisions from a total of 9 televisions)
Hence, we get:

b)
The probability at least one of the two televisions does not work:
Is equal to the probability that one does not work+probability both do not work.
Probability one does not work is calculated by:

and the probability both do not work is:

Hence, Probability that atleast does not work is:
0.5+0.0833=0.5833
Five dimes and one quarter = .75.
9.75/.75=3.25*4/1=13
there are 13 "5 dimes and 1 quarter"s
so 65 dimes