Answer:
x = 8, and y = 12
Step-by-step explanation:
There are 2 variables, so you need 2 equations to form a system of equations in two variables.
The upper left triangle has all angle measures given: 100, 2x + y, 5x + y. We know that the sum of the measures of the angles of a triangle is 180.
First equation:
100 + 2x + y + 5x + y = 180
Simplify:
7x + 2y = 80 (First equation)
Now we see that the upper and lower sides are parallel, so alternate interior angles are congruent. The angles measuring 2x + y and 5x - y are alternate interior angles and are congruent.
Second equation:
2x + y = 5x - y
Simplify:
3x - 2y = 0 (Second equation)
Now we use the first equation and the second equation as a system of simultaneous equations to solve for x and y.
7x + 2y = 80
3x - 2y = 0
Solve the second equation for 2x.
3x = 2y
Now replace 2y in the first equation with 3x.
7x + 3x = 80
10x = 80
x = 8
Replace x with 8 in the second equation.
3(8) - 2x = 0
24 = 2x
x = 12
Answer: x = 8, and y = 12
<span>circumference of circle = 2*pi*r
given r = 5
so circumference = 31.42
now we know 360 degree is uniformly distributed on this circumference
so x/360=10/31.42
so x= 114.65
so option C.) 114.65 is the answer</span>
Right Triangles and the Pythagorean Theorem
The Pythagorean Theorem, a2+b2=c2, a 2 + b 2 = c 2 , can be used to find the length of any side of a right triangle.
The side opposite the right angle is called the hypotenuse (side c in the figure).
I'll use my own formula (similar to yours tho)

A=future amount
p=invested
r=rate in decimal
n=number of times per year compounded
t=time in years
so
when will A=2P
subsitute 2P for A
also quarterly means 4 times a year or n=4
and 12%=0.12=r
so

divide both sides by P

simplify


take the ln of both sides



divide both sides by 4ln(1.03)

use calculator
5.86244=t
about 5.9 years
86.3 / 30 = 2.876
Therfore the answer is D $2.88