Answer:
x=-5
Step-by-step explanation:
![3x-7=7x+13\\\\3x-7+7=7x+13+7\\\\3x=7x+20\\\\3x-7x=7x+20-7x\\\\-4x=20\\\\\frac{-1}{4}(-4x) =\frac{-1}{4}(20)\\\\x=-5](https://tex.z-dn.net/?f=3x-7%3D7x%2B13%5C%5C%5C%5C3x-7%2B7%3D7x%2B13%2B7%5C%5C%5C%5C3x%3D7x%2B20%5C%5C%5C%5C3x-7x%3D7x%2B20-7x%5C%5C%5C%5C-4x%3D20%5C%5C%5C%5C%5Cfrac%7B-1%7D%7B4%7D%28-4x%29%20%3D%5Cfrac%7B-1%7D%7B4%7D%2820%29%5C%5C%5C%5Cx%3D-5)
Answer:
300
Step-by-step explanation:
The volume of the gas varies inversely as the pressure
V= k/p
K= VP
= 1200×200
= 240,000
Therefore the volume when the pressure is 800
K= VP
240000= V×800
V= 240000/800
= 300
Hence the volume is 300 cubic centimeters
A-students taking band
B-students taking chorus
|AuB| = 250
|A| = 180
[AnB] = 60
|AuB| = |A| + |B| - |AnB|
|B| = |AuB| - |A| + |AnB| = 250 - 180 + 60 = 130
ans: 130 students in chorus only