Given that:
(x+2)(2x-5)=54
We have:

Using the quadratic formula, this is approximately 5.66, so rounded to the nearest whole number, our answer is 6.
Answer:
7.8
Step-by-step explanation:
Prob (first defective) = 4 / 20 = 1/5
Prob(2nd defective) = 3/19
Prob (3rd defective) = 2/18 = 1/9
Pron 4th defective) = 1/ 17
Prob ( all 4 defective) = 1/5 * 3/19 * 1/9 * 1/17 = 1 / 4845 answer
9 students, 4 are selected and order doesn't matter:
Go to the 9th row of the triangle (mind you the first row is 0), the 2nd is 1st row
9th row: 1 9 36 84 126 126 84 36 9 1
Now choose the 4th column (excluding the 1st , you will get 126 :
so 126 is the number of combination requested:
PROOF: ⁹C₄ = 9!/(9-4)! .4! = (9!)/5!.4! = 126
Answer: the answer is 8 because
Step-by-step explanation: