Answer:
9
Step-by-step explanation:
Let's first convert this to numbers. When a number is decreased by a certain amount, that is the same as saying that something is subtracted from it. Therefore:
a-7=2
Add 7 to both sides:
a-7+7=2+7
a=9
Hope this helps!
A, C, And D
Could be these answers...
I'm not sure what you mean by difference, so I am guessing you meant to write "distance". If this is not the case, then feel free to report me. Anyway, to find the distance between two points you would use the distance formula.
Distance Formula: 
.
Let's substitute our point coordinates into the formula. We'll substitute -1 and 6 for x_2 and x_1, and 14 and 16 for y_2 and y_1. After substituting, your formula will now look like: 
.
Subtract the coordinates.
Square the subtracted coordinates.
Add 49 and 4.
Square root 53 and round the answer to the nearest tenth.
7.28 becomes 7.3.
7.3 units is the distance between points M and Z.
Step-by-step explanation:
Use the standard form to write two equations using points A and B:
(
−
2
−
h
)
2
+
(
0
−
k
)
2
=
r
2
(
5
−
h
)
2
+
(
1
−
k
)
2
=
r
2
Because
r
2
=
r
2
, we can set the left sides equal:
(
−
2
−
h
)
2
+
(
0
−
k
)
2
=
(
5
−
h
)
2
+
(
1
−
k
)
2
Expand the squares using the pattern
(
a
−
b
)
2
=
a
2
−
2
a
b
+
b
2
4
+
4
h
+
h
2
+
k
2
=
25
−
10
h
+
h
2
+
1
−
2
k
+
k
2
Combine like terms (noting that the squares cancel):
4
+
4
h
=
25
−
10
h
+
1
−
2
k
Move the k term the left and all other terms to the right:
2
k
=
−
14
h
+
22
Divide by 2
k
=
−
7
h
+
11
[1]
Evaluate the given line at the center point:
2
h
+
k
−
1
=
0
Write in slope-intercept form
k
=
−
2
h
+
1
[2]
Subtract equation [2] from equation [1]:
k
−
k
=
−
7
h
+
2
h
+
11
−
1
0
=
−
5
h
+
10
h
=
2
Substitute 2 for h in equation [2]
k
=
−
2
(
2
)
+
1
k
=
−
3
Substitute the center
(
2
,
−
3
)
into the equation of a circle using point A and solve for the value of r:
(
−
2
−
2
)
2
+
(
0
−
−
3
)
2
=
r
2
(
−
4
)
2
+
3
2
=
r
2
r
2
=
25
r
=
5
Substitute the center
(
2
,
−
3
)
and #r = 5 into the general equation of a circle, to obtain the specific equation for this circle:
(
x
−
2
)
2
+
(
y
−
−
3
)
2
=
5
2
