Answer:
Step-by-step explanation:
y^2 + x^2 = 65
y + x = 7......x = 7 - y
y^2 + (7 - y)^2 = 65
y^2 + (7 - y)(7 - y) = 65
y^2 + 49 - 7y - 7y + y^2 = 65
2y^2 - 14y + 49 = 65
2y^2 - 14y + 49 - 65 = 0
2y^2 - 14y - 16 = 0
2(y^2 - 7y - 8) = 0
2(y + 1)(y - 8) = 0
y + 1 = 0 y - 8 = 0
y = -1 y = 8
solution :
y = -1...........y + x = 7.....-1 + x = 7......x = 7 + 1......x = 8........(8,-1)
y = 8........y + x = 7.....8 + x = 7......x = 7 - 8........x = -1........(-1,8)
Area of a circle is directly proportional to the square of radius of the circle while the circumference is proportional to the radius of the circle. This means that if the radius of a circle is increased x times, then its area will be increased to x^2 times the original area, and the circumference will increase to x times the original circumference.
Thus when the radius is doubled, or in other words if radius mad 2 time the original radius, the area of circle will become 2^2 = 4 time the original area. The circumference will become 2 times the original circumference.
We can calculate exact area and circumference of a circle from its radius using the following equations:
Area of circle = (pi/4)*r^2
Circumference of circle = 2*pi*r
Where r is the radius of the circle.
I know this is a lot, sorry.
ASSUMING This is a straight line so we gotta the formula for a straight line which is y=mx+b, where m represents the slope and b represents the y intercept.
First, we know this line passes through (5,8) and (9,2) we can use these for finding the equations. When we know two points, we use this formula:
y-y=m(x-x)
The first y is 8 and the second one is 2
The first x is 5 and the second one is 9
Plug it in:
8-2=m(5-9)
6=m(-4)
6/-4=m <— simplify this
m= -3/2
*NOTE: another way to find m is by calculating it (y-y)/(x-x)
Now we know m, we have to find b.
All you gotta do is plug everything you know back into the equation y=mx+b
y=mx+b
y=-3/2x+b <— now plug in a point we know(x,y)
8=-3/2(5)+b
8=-15/2+b
8-(-15/2)=b
b=8+15/2
b=16/2+15/2
b=31/2 (now you can write be as a fraction or a decimal in your equation, depending on what your teacher told you to use)
*NOTE: it is best to use fractions instead of decimals as it is more accurate sometimes.
Now we know all the variables that need to be known, we just need to rewrite the formula of the equation so the teacher can see.
m=-3/2
b=31/2
We don’t need to plug in x or y since it could have different values (since a straight line has MANY co-ordinates)
SO OUR EQUATION IS=
y=(-3/2)x+31/2
Hope you understand this, feel free to ask me anything!
The sign would be negative
Melissa tem 16 moedas
Juan tem o dobro, ou seja, 16 x 2 = 32
Na adição vai ser o mesmo resultado
16+16=32
Se eles juntos tivessem 144 moedas.
Calculando
144 ÷ 2 = ou seja dividido por duas pessoas sendo melissa e juan
R = juan tem 72 moedas.
Cada um vai ficar com 72 moedas