So we have the following system of equations:

We need to solve it by substitution. This means that we have to take the expression for x given by the second equation and replace x with it in the first equation:

So y=-1. If we use this value in the second equation:

So we have x=2 and y=-1 which means that there's one solution. Then the correct answer is A and the solution is (2,-1).
Answer:
21, 9
Step-by-step explanation:
If girls are x, then boys are x + 12
x + x + 12 = 30
2x + 12 = 30
2x = 18
x = 9
There are 9 girls and 21 boys
The standard equation of a circle is given by:
(x-a)²+(y-b)²=r²
where:
(a,b) is the center and r is the radius.
Given that (a,b) is (-8,-3) and r=2 units
then the equation of the circle will be:
(x-(-8))²+(y-(-3))²=2²
simplifying the above we get:
(x+8)²+(y+3)²=4