Answer:
A
Step-by-step explanation:
The correct answer is A, x+2y=0
Let x be the number of nickels and y be the number of quarters.
Then, x + y = 42 --- (1)
It is given that total value = 4.90.
Therefore, 0.05x + 0.25y = 4.9 --- (2)
Multiply (1) by 0.25
0.25x + 0.25y = 10.5 --- (3)
Now, subtract (2) from (3), we get,
0.2x = 5.6
Divide both sides by 0.2.
x = 28
x + y = 42
y = 42 - x
= 42 - 28
= 14
Hence, Mary has 28 nickels and 14 quarters in total.
4. one solution is (1, 3)
5. (1, -1)
7. -5 = x + 3
x = -5 - 3
x = -8
8. z - 4 = -8
z = -8 + 4
z = -4
Answer: 480 mL, 600 mL
Step-by-step explanation:
Given
The concentration of the first acid is 75%
The concentration of the second acid is 30%
The final mixture has a concentration of 50%
The final volume is 1080 mL
Suppose x and y be the volume of the first and second acid
Solving the above equations we get
So, the quantity of the first acid is 480 mL and 600 mL for the second mixture.
Answer:
You may be asked to "determine algebraically" whether a function is even or odd. To do this, you take the function and plug –x in for x, and then simplify. If you end up with the exact same function that you started with (that is, if f (–x) = f (x), so all of the signs are the same), then the function is even.
