a3=9
assuming the pattern is constant, a3 is right in the middle of a1 and a5 so the answer would be right in the middle of 6 and 12. the average of 6 and 12 is 9, so a3=9.
hope this helps!
Step-by-step explanation:
8x + x² - 2y + y² - 64 = 0
(x + 4)² + (y - 1)² - 81 = 0
(x + 4)² + (y - 1)² = 81
Hencr the center is (-4,1) and the radius is 9.
It is not an irrational number
Slope: 5/1 (5 if simplified)
y-intercept: 10
x = 37.5 (or) 
Solution:
Given 
AC = 50, DE = 30, EC = 25, BE = x, BC = 25 + x
To find the value of x:
Property of similar triangles:
If two triangles are similar then the corresponding angles are congruent and the corresponding sides are in proportion.


Do cross multiplication, we get


Subtract 30x from both sides of the equation.

Divide by 20 on both sides of the equation, we get
x = 37.5 (or) 
Hence the value of x is 37.5 or
.