The answer will be 27 only.
The general equation of a circle is

where a and b are the x and y components of the center respectively.
In order to get into this format, we have to use a method that I'm drawing a blank on the same, my apologies about that.
Anyway, what you want is to first isolate the variable on side so now you have:

(you'll see why I rearranged this soon)
Now you have to make it into an equation that can be simplified into the format stated earlier.
So, You have to take the x & y terms (-4x & -8y in this case) divide them each by two, and then square them.
The result of this step is the equation:
Notice the new components that have been added (4 & 16) and how the have been
added to both sides. That is an important step.
Now we simplify and get:

So the coordinate of the center is: (2,4) and the radius is 5
Answer:
a= 18 girls in the class, b= 20 boys and 15 girls, 12 oranges better price.
Step-by-step explanation:
for question a, there are 18 girls in the class, this is how i worked it out:
the ratio of boys to girls is 4:3.
there are 24 boys.
24 is 6 times more than 4.
if boys are 6 times more than the original ratio, we also have to times the amount of girls by 6.
6x3= 18.
for question b i got 20 boys and 15 girls, this is how i did it.
there are 35 students in total.
4:3= boys to girls.
4+3=7
7 goes into 35 five times.
ratio of boys to girls is 4:3 so 5x4 for boys = 20 and 3x5 for girls = 15.
answer= 20 boys and 15 girls.
12 oranges is a better deal, this is how i worked it out.
it is 60 for 12 oranges.
it is 48 for 8 oranges.
12x5= 60 , 8x6=48.
you only have to times 12 by 5 to get it to the price but you have to times 8 by 6 to get it to the price, proving that 12 oranges for 60 is a better deal.
Answer:
- Just plug in the values and the calculate :



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