Answer:
9
Step-by-step explanation:
Compare your x2 + y2=81 to the following:
x^2 + y^2 = 81
The " ^ " symbol indicates exponentiation.
Now compare x^2 + y^2 = 81 to
x^2 + y^2 = r^2.
This is the standard equation of a circle of radius r centered at the origin, (0,0). You can see for yourself that 81 must equal r^2.
Taking the square root of 81, we get plus or minus 9.
But the radius must be positive, so we reject the -9 and take +9.
The radius is 9.
Answer:

Step-by-step explanation:
<-- Given
<-- Distributive Property
<-- Find LCD of x-terms
<-- Combine Like Terms
<-- Add 45/8 to both sides
<-- Simplify Right Side
<-- Subtract 7 on both sides
<-- Divide both sides by 289/60
ANSWER

EXPLANATION
Recall that,

That is why

is equivalent to

This implies that,

This is the same as,

When we are dividing by

we move the decimal point backwards two times.
This implies that,
Answer:
8
Step-by-step explanation:
1. 3b - 2 (1 - b) / a - 2
2. 3(2) - 2 (1 - 2) / 3 - 2
3. 6 - 2 (-1) / 1
4. 6 + 2 / 1
5. 8 / 1
6. 8