Answer:
A(2,2)
Step-by-step explanation:
Let the vertex A has coordinates 
Vectors AB and AB' are perpendicular, then

Vectors AC and AC' are perpendicular, then

Now, solve the system of two equations:

Subtract these two equations:

Substitute it into the first equation:

Then

Rotation by 90° counterclockwise about A(2,2) gives image points B' and C' (see attached diagram)
Answer:
i think A
Step-by-step explanation:
Let us take a number x
The four consecutive numbers will be
x+1, x+2, x+3
Thus our equation will be
x + x+1 + x+2 + x+3 = 42
4x + 6 = 42
4x = 36
x= 36/4
x= 9
Thus the four numbers are (substitute)
x=9
x+1=9+1=10
x+2=9+2=11
x+3=9+3=12
9,10,11,12