Answer:
Below in bold.
Step-by-step explanation:
If the 3 points are on the circle with the given center then the distance from each point to the center will all be equal. This distance will be the radius of the circle.
Distance of P (2, 5) from the center (4, 2)
= √( (5-2)^2 + (2-4)^2)
= √(9 + 4)
= √13.
For Q (6, -1)this distance is:
= √(6-4)^2 + (-1-2)^2)
= √13.
For R (7, 4) his distance is:
= √(7-4)^2 + (4-2)^2)
= √13
These distances are the same so the points P, Q and R lie on the circle.
The midpoint of PQ
= (2+6)/2 , (5 - 1)/2
= (4, 2).
Which is the center so this verifies the second part.
2 1/4 = 2 3/12
16 2/3 = 16 8/12
16 8/12 + 2 3/12 = 18 11/12
The exponents distribute over factors:

so, you have

Let's focus on each factor: applying the definition of negative exponents, you have

While for the power of 10, you can use the following rule
to write

So, the expression evaluates to
