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A few math problems I'm having trouble with? Can someone help me?
I've tried to understand this and still just don't get it? Can someone help me please? And if you give the answer can you explain how you got it?
1. The function f(x) varies directly with x and f(x) = 90 when x = 30. What is f(x) when x = 6?
A) 2
B) 5
C) 15
D) 18
Is it 18?
2. The function f(x) varies inversely with x and f(x) = 2 when x = 16. What is f(x) when x = 4?
A) 128
B) 72
C) 40
D) 8
I have no clue on this one
3. The pressure of a gas p(v) varies inversely with the volume of the gas v. The pressure of a gas measures 15kg/cm2 when it's volume is 390cm3 Which equation can be used to find the pressure of the gas when the volume is changed?
A. P(v) = 20v
B. P((v) = 20/v
C. P(v) = 4500v
D. (P)v = 4500/v
1 Answer
- hayharbrLv 75 years agoFavorite Answer
1. If f(x) and x vary directly, their ratio is always the same. So 90/30 = f(x)/6. Cross multiply and solve.
30 f(x) = 540
f(x) = 18 so yes it's 18
2. If they vary inversely, their product is always the same.. So 2• 16 = 4 • f(x)
32 = 4 f(x)
8 = f(x)
and 15 • 390 = P(v) • v
which gives me 5850 = P(v) • v so P(v) would be 5850/v uh oh any chance the 390 is really 300??
