Answer:

Step-by-step explanation:
(4/3)P -(4/3)A + A = B . . . . . . add A
(4P -A)/3 = B . . . . . . . . . . . . . simplify
Then the coordinates of point B are ...
B = (4(1, 6) -(-5, 3))/3 = (9, 21)/3
B = (3, 7)
Answer:
0.5 < x < 16.5
Step-by-step explanation:
The third side of the triangle must be longer than the difference of the other two sides:
x > (8.5 -8.0)
x > 0.5
And it must be shorter than their sum:
x < (8.5 +8.0)
x < 16.5
The third side must be in the range ...
0.5 < x < 16.5
_____
These limits are a direct consequence of the triangle inequality, which requires the sum of the two shortest sides exceed the length of the longest side.
The mean is calculated by adding up all of the given numbers and dividing by the number of numbers.
Lets, for ease of understanding, say that the first three number were 64...
Mean=(64+64+64)/3=192/3=64
Now, lets solve for the mean where 'x' is the unknown fourth number and 128 is the mean. (since, the answer said that when the fourth number was added the mean, 64, was doubled '64*2=128')
128=(64+64+64+x)/4
128=(192+x)/4
Multiply both sides by 4
512=192+x
subtract 192 from both sides
320=x
The missing number is 320..
Now lets double check our work.
Mean=(64+64+64+320)/4=512/4=128
Answer=320