Answer:
Step-by-step explanation:
There are a total of 7 + 9 + 2 = 18 balls in the vase, therefore, when not replacing the first ball, there would be 18 · 17 = 306 ways to pull 2 balls. There are 2 ways to choose the first black ball and then 1 way to choose the second black ball so there are 2 · 1 = 2 ways to choose 2 black balls. Therefore, the probability is 2 / 306 = .
Answer:
1. x = +/- 2 - 7
2. x = +/-
3. n = +/-
Step-by-step explanation:
1. Divide both sides by 2: (x + 7)^2 = 8
Square root both sides: x + 7 = +/- 2
Subtract 7 from both sides: x = +/- 2 - 7
2. Square root both sides: x - 3 =
Since there is a negative inside the radical, we need to have an imaginary number: . So,
Add 3 to both sides: x = +/-
3. Divide by -5 from both sides: (n - 2)^2 = -2
Square root both sides: n - 2 =
Again, we have to use i:
Add 2 to both sides: n = +/-
Hope this helps!