X2 + 4x - 21
Answer: (x + 7)(x - 3)
You’re gonna have to use the quadratic formula here and a bit of thinking. We know y is height, and once it touches the ground, it will be 0.
(-b +- sqrt b^2 - 4ac)/2a
2 +- sqrt(4 + 48(400))/-32
(2 +- 138.58)/-32
We don’t want a negative time because it’ll make no sense. So do subtraction
(2-138.58)/-32 = 4.27 seconds aka 4.3 seconds
Given:
Cards labelled 1, 3, 5, 6, 8 and 9.
A card is drawn and not replaced. Then a second card is drawn at random.
To find:
The probability of drawing 2 even numbers.
Solution:
We have,
Even number cards = 6, 8
Odd numbers cards = 1, 3, 5, 9
Total cards = 1, 3, 5, 6, 8 and 9
Number of even cards = 2
Number of total cards = 6
So, the probability of getting an even card in first draw is:



Now,
Number of remaining even cards = 1
Number of remaining cards = 5
So, the probability of getting an even card in second draw is:


The probability of drawing 2 even numbers is:



Therefore, the probability of drawing 2 even numbers is
. Hence, the correct option is (b).