Answer:
x + 3y = 21
Step-by-step explanation:

Equation of the line: y =mx+ b

Multiply the equation by 3
3y = -x + 21
x + 3y = 21
Answer: 12 friends.
Step-by-step explanation:
the data we have is:
Mei Su had 80 coins.
She gave the coins to her friends, in such a way that every friend got a different number of coins, then we have that:
The maximum number of friends that could have coins is when:
friend 1 got 1 coin
friend 2 got 2 coins
friend 3 got 3 coins
friend N got N coins
in such a way that:
(1 + 2 + 3 + ... + N) ≥ 79
I use 79 because "she gave most of the coins", not all.
We want to find the maximum possible N.
Then let's calculate:
1 + 2 + 3 + 4 + 5 = 15
15 + 6 + 7 + 8 + 9 + 10 = 55
now we are close, lets add by one number:
55 + 11 = 66
66 + 12 = 78
now, we can not add more because we will have a number larger than 80.
Then we have N = 12
This means that the maximum number of friends is 12.
Answer:
, 
Step-by-step explanation:
Given
the equation is 
completing the square

Thus, the center of the circle is
and radius is 
9514 1404 393
Answer:
60 square units
Step-by-step explanation:
The area is given by the formula ...
A = bh
The base of this parallelogram is 15 units, and its height is 4 units. The area is ...
A = (15 u)(4 u) = 60 u²
The area is 60 square units.
The sum of the magnitudes will be the magnitude of the sum when the vectors have the same direction.