I would start like this: which year was the seventh AMC 8??
the first was in 1985
The second: 1986
3: 1987
4: 1988
5: 1989
6: 1990
7: 1991
so seventh AMC 8 took place in 1991.
she was then 12, so we can subtract this age from 1991:
1991-12=1979
so she was born in 1979!
Step-by-step answer:
This is a regular heptagon, means it has 7 <em>congruent</em> sides and 7 <em>congruent </em>vertex angles.
To work with polygons, there is a very important piece of information that you must know to solve the majority of related problems.
This is:
sum of exterior angles of polygons = 360 degrees.
If you don't remember the 360 degrees, think of the sum of exterior angles of an equilateral triangle, which is 3*(180-60)=3*120=360! It works!
For a regular heptagon, c = 360/7=51.43 degrees approx.
This means that each vertex angle measures
vertex angle = 180-c
So since 2d+the vertex angle = 360, we have
2d+(180-c)=360
solve for d:
2d=360-(180-c)=180+c
d=(180+c)/2=90+c/2=115.71 degrees. (approx.)
Add both the equations together to eliminate x
x+5y=8
-x+2y=-1
7y=7
y=1
Now fill in y into the original equation
x+5(1)=8
x+5=8
x=3
Now you can check by filling x and y into the second equation.
-(3)+2(1)=-1
-3+2=-1
-1=-1
So your answer will be (3, 1)
Brainliest my answer if it helps you out?
<em>Note: I am assuming the first equation is:</em>
<em>x+y = 3</em>
Answer:
The solution to the system of equations is:
(x, y) = (-2, 36)
Therefore, the x-coordinate of the solution of the system
x = -2
Step-by-step explanation:
Given the system of equations
subtracting the equations
solve -2y for y
Divide both sides by -2
For x+y=34 plug in y = 36
Subtract 36 from both sides
Simplify
Thus, the solution to the system of equations is:
(x, y) = (-2, 36)
Therefore, the x-coordinate of the solution of the system
x = -2
