At the mall Greg purchased three CDs which cost $10.68 each if Greg has $79 in his wallet before the purchase how much money is
2 answers:
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Answer:
a). Center of the circle = (-2, 5)
b). Equation of the line ⇒ y =
Step-by-step explanation:
Equation of the circle is,
x² + 4x + y²- 10y + 20 = 30
a). [x² + 2(2)x + 4 - 4] + [y²- 2(5)y + 25] - 25 + 20 = 30
[x² + 2(2)x + 4] - 4 + [y² - 2(5)y + 25] - 25 + 20 = 30
(x + 2)² + (y - 5)²- 29 + 20 = 30
(x + 2)² + (y - 5)²- 9 = 30
(x + 2)² + (y - 5)² = 39
By comparing this equation with the standard equation of a circle,
Center of the circle is (-2, 5).
b). A point (2, 10) lies on this circle.
Slope of the line joining this point to the center (-2, 5),
=
=
Let the slope of the tangent which is perpendicular to this line is ''
Then by the property of perpendicular lines,
Now the equation of the line passing though (2, 10) having slope
y - y' =
y - 10 =
y - 10 =
y =
y =
Therefore, equation of the line will be, y =
Answers:
P(A) = 7/12
P(B) = 1/4
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Explanation:
Instead of having one die, let's say we have two dice. I'll make one red and the other blue.
I'll be using the dice chart shown below. The red and blue values add up to the black numbers inside the table. For instance, we have 1+1 = 2 in the upper left corner. There are 6*6 = 36 sums total.
Using that table, we can see the following:
- There are 6 copies of "7"
- There are 5 copies of "8"
- There are 4 copies of "9"
- There are 3 copies of "10"
- There are 2 copies of "11"
- There is 1 copy of "12"
In total, we have 6+5+4+3+2+1 = 21 instances where the two dice add to something larger than 6.
This is out of 36 ways to roll two dice.
Therefore P(A) = 21/36 = (3*7)/(3*12) = 7/12
-----------------------------------
If a number is divisible by 4, then it is a multiple of 4.
The multiples of 4 found in the table are: 4, 8, 12
We have
- 3 copies of "4"
- 5 copies of "8"
- 1 copy of "12"
This gives 1+5+3 = 9 values that are a multiple of 4
P(B) = 9/36 = (1*9)/(4*9) = 1/4
