Answer:
Gina is 12 years old
Step-by-step explanation:
First, we will have to write these statements mathematically and then solve.
Let Gina's age be x, let Gina's brother's age be y and let Gina's sister's age be z.
The second statement"Gina's older sister is twice Gina's age" can be mathematically written as: z =2 x ---------------------------(1)
The next statement "Gina's brother is half Gina's age" can be mathematically written as y = 
---------------------------------------(2)
Then the next statement "the sum of their ages is 42" can be mathematically written as: x + y + z = 42 ----------------------------(3)
We can now proceed to solve;
Substitute equation (1) and equation(2) into equation (3)
x + y + z = 42
x + + 2x = 42
Multiply through by 2
2x + x + 4x = 84
7x = 84
Divide both-side of the equation by 7
= 
x = 12
Therefore, Gina is 12 years old
G = x
Felicia is Gabriella's age + 6
F = x + 6
Their mother is twice Felicia's age
M = 2(x + 6) or 2x + 12
Tanya is the age of their mother plus Gabriella's age
A = 2x + 12 + x = 3x + 12
3x + 12
The given equation of the ellipse is x^2
+ y^2 = 2 x + 2 y
At tangent line, the point is horizontal with the x-axis
therefore slope = dy / dx = 0
<span>So we have to take the 1st derivative of the equation
then equate dy / dx to zero.</span>
x^2 + y^2 = 2 x + 2 y
x^2 – 2 x = 2 y – y^2
(2x – 2) dx = (2 – 2y) dy
(2x – 2) / (2 – 2y) = 0
2x – 2 = 0
x = 1
To find for y, we go back to the original equation then substitute
the value of x.
x^2 + y^2 = 2 x + 2 y
1^2 + y^2 = 2 * 1 + 2 y
y^2 – 2y + 1 – 2 = 0
y^2 – 2y – 1 = 0
Finding the roots using the quadratic formula:
y = [-(- 2) ± sqrt ( (-2)^2 – 4*1*-1)] / 2*1
y = 1 ± 2.828
y = -1.828 , 3.828
<span>Therefore the tangents are parallel to the x-axis at points (1, -1.828)
and (1, 3.828).</span>
Answer:
8
Step-by-step explanation:
2+(3×2)=2+6=8
<span>Look at your table for a Z value of 1.55. The numbers on the far left column are your z values. See the 1.5 row, then move over to the 0.05 column to make it 1.55.
You'll see 0.9394.
That's the area under the normal curve from 1.55 to negative infinity.
But you wanted the area under the curve greater than 1.55.
Take 1-0.9394=0.0606.
You subtract from 1 because you know that the area under the whole curve is 1, so it gives you the area you need.</span>
