Answer:
y=2
Step-by-step explanation:
Answer:
First brand of antifreeze: 21 gallons
Second brand of antifreeze: 9 gallons
Step-by-step explanation:
Let's call A the amount of first brand of antifreeze. 20% pure antifreeze
Let's call B the amount of second brand of antifreeze. 70% pure antifreeze
The resulting mixture should have 35% pure antifreeze, and 30 gallons.
Then we know that the total amount of mixture will be:

Then the total amount of pure antifreeze in the mixture will be:


Then we have two equations and two unknowns so we solve the system of equations. Multiply the first equation by -0.7 and add it to the second equation:



+

--------------------------------------



We substitute the value of A into one of the two equations and solve for B.


Answer: y = -5
Substitute in 3 for x.
x - y = 8 Substitution
3 - y = 8 Subtract 3 from both sides
-y = 5 Divide by -1 to both sides
y = -5 Answer!
You can also check your work.
x - y = 8
3 - (-5) = 8
3 + 5 = 8
8 = 8
Answer:
The real perimeter is:

And the area would be:

Step-by-step explanation:
For this case we know one side of a square given 6mm.
We can begin calculating the perimeter for the scale figure with this formula:

The area for this case is given by:

And we know that the drawing has a scale of 1 mm : 7 km and if we convert the perimeter to km we got:

And the area would be:

Answer:
The surface area of the award is 
Step-by-step explanation:
we know that
The surface area of the square pyramid is equal to the area of the square base plus the area of its four lateral triangular faces
so
![SA=6^{2}+4[\frac{1}{2}(6)(8)]=132\ in^{2}](https://tex.z-dn.net/?f=SA%3D6%5E%7B2%7D%2B4%5B%5Cfrac%7B1%7D%7B2%7D%286%29%288%29%5D%3D132%5C%20in%5E%7B2%7D)