Answer:
Step-by-step explanation:
x-y=7
-3x+9y=-39
Divide the second equation by 3
-x +3y = -13
Add this to the first equation
x-y=7
-x +3y = -13
----------------------
0x +2y = -6
Divide by 2
2y/2 = -6/2
y = -3
Now find x
x-y = 7
x -(-3) = 7
x+3 = 7
Subtract 3 from each side
x = 4
(4,-3)
Or by substitution
x-y=7
solve for x
x = 7+y
-3x+9y=-39
Substitute y+7 in for x
-3(7+y) +9y = -39
Distribute
-21 -3y +9y = -39
Combine like terms
-21 +6y = -39
Add 21 to each side
6y = -18
Answer:
The perimeter is 1280ft
Step-by-step explanation:
Let the side length of the square be s.
Then the distance around three sides is 3s.
According to the question the distance around 3 sides of a square city block is 960 feet.
This implies that:



The perimeter of a square is

Substitute s=320 to get:


The perimeter is 1280 ft
When x=9 the expression is undefined.
That is because any number over 0 is undefined, including 0/0.
Answer:
-9
-6
-4
-3
0
Step-by-step explanation:
hope this helps!
<span>The answer to this problem is B. 24 + 26 + 31 + 22. </span>