Answer:
(-4, -1)
Step-by-step explanation:
x = 4y
-4x - y = 17
Plug in 4y for x in the second equation:
-4(4y) - y = 17
Simplify. Remember to follow PEMDAS. Isolate the variable, y. Note the equal sign, what you do to one side, you do to the other.
First, multiply 4y with -4:
-4(4y) = -16y
-16y - y = 17
Simplify. Combine like terms:
-16y - y = 17
-17y = 17
Isolate the variable, y. Divide -17 from both sides:
(-17y)/-17 = (17)/-17
y = 17/-17
y = -1
Plug in -1 for y in the first equation:
x = 4y
x = 4(-1)
x = -4
x = -4, y = -1
Answer: (-4, -1)
~
A tank with capacity T gallons is empty. Tank will be filled in 
minutes
<u>Solution:</u>
Given, A tank with capacity T gallons is empty.
We have to find how many minutes will tank be filled?
Now, Water flows into the tank from pipe X at the rate of X gallons per minute,
And water is pumped out by pipe Y at the rate Y gallons per minute,
Then, together in one minute the amount of water filled will be x – y gallons [as X is greater than Y]
Now, the time take to fill tank = 
Hence tank will be filled in minutes
Given:
1 inch : 18 kilometers
Let us use the ratio and proportion method:
a:b = c:d where ad = bc
0.8 inches is <u>14.4 kilometers</u>
1 : 18 = 0.8 : x
x = 0.8 * 18
x = 14.4 km
1.4 inches is <u>25.2 kilometers</u>
1: 18 = 1.4 : x
x = 18 * 1.4
x = 25.2 km
2.1 inches is <u>37.8 kilometers</u>
1 : 18 = 2.1 : x
x = 18 * 2.1
x = 37.8 km
This problem can be solved using the concepts of permutation.
Zzyzx is the word. It has five letters. It asked as to how many five-letter arrangements of the letters in the English alphabet follow Zzyzx alphabetically.
Take note: <span>alphabetically
</span>
The two remaining five-letter after Zzyzx are Zzyzy and Zzyzz.
The remaining arrangements are of the form Zzz _ _.
There are 26 × 26 = 676 ways to fill in the last two letters, so following Zzyzx alphabetically, there are 2 + 676 = 678 arrangements.
