Answer:

Step-by-step explanation:
A quick review on PEMDAS, the order of how to solve an equation:
P - parentheses. When parentheses are being used, you have to do everything inside them before doing everything outside of them.
E - exponents. We'll skip these, since there aren't any exponents we need to worry about in this equation.
M/D - multiplication/division. I include these both together because they can be done at the same time.
A/S = addition/subtraction. Can also be done at the same time.
Some other things to note:
You add all the things with an x attached to it, and you add all the things without an x attached to it, and these never cross.
When you bring something from one side of an equal sign to another, you make it negative.
Let's solve for x using what we've learned:

18 kg of 15% copper and 72 kg of 60% copper should be combined by the metalworker to create 90 kg of 51% copper alloy.
<u>Step-by-step explanation:</u>
Let x = kg of 15% copper alloy
Let y = kg of 60% copper alloy
Since we need to create 90 kg of alloy we know:
x + y = 90
51% of 90 kg = 45.9 kg of copper
So we're interested in creating 45.9 kg of copper
We need some amount of 15% copper and some amount of 60% copper to create 45.9 kg of copper:
0.15x + 0.60y = 45.9
but
x + y = 90
x= 90 - y
substituting that value in for x
0.15(90 - y) + 0.60y = 45.9
13.5 - 0.15y + 0.60y = 45.9
0.45y = 32.4
y = 72
Substituting this y value to solve for x gives:
x + y = 90
x= 90-72
x=18
Therefore, in order to create 90kg of 51% alloy, we'd need 18 kg of 15% copper and 72 kg of 60% copper.
Answer:
The triangle is translated 2 units down and 4 units to the right.
Step-by-step explanation:
Answer:
246.
Step-by-step explanation:
Let the number be 2xy, then
2 + x + y = 2y and y must be even because the whole number is even.
y = 2 + x .
Now x must be even because y is even.
The only 2 numbers which fit are x = 4 and y = 6 so the number is 246.
Checking: 2+4+6 = 12 and 12 = 2*6.
Answer:
Step-by-step explanation:
Welllllll.....
If you take the square root of 9, it's 3
if you take the square root if 16, it's 4
I would guess it to be about 3.2