Which systems of equations have exactly one solution?
choose all answers that are correct.
1. y = 2x
y=2x+1
2 . x =5
y = -4
3. y = x+6
y -6 =x
4 . y= 3x+ 4
y =3

Circle a has a diameter of 7 inches, a circumference of 21.98 inches, and an area of 38.465 square inches. the diameter of circle b is 6 inches, the circumference is 18.84 inches, and the area is 28.26 square inches. part a: using the formula for circumference, solve for the value of pi for each circle. (4 points) part b: use the formula for area and solve for the value of pi for each circle. (4 points)