please help with these math problems?

For the following problem, y varies directly as x. => y = kx
If y = 12 when x = 16, find x when y is 15. Solve for k: 12= k*16 =>k = 12/16 = 3/4 =>15=3x/4
x = 20 <------

1. For the following problem, y varies directly as the square of x. y= kx²
If y = −50 when x = 5, -50 = k5² = k*25 => k = -2 find y when x is 8 => y = -2*8². = -128 <----- 1.
2. For the following problem, y varies inversely with x. y=k/x If y = 4 when x = 1, => k = 4 find y when x is 6 => y = 4/6 = 2/3 <---- 2.
3. For the following problem, y varies inversely as the square of x. y=k/x² => 48=k/2² => k = 192
If y = 48 when x = 2, find y when x is 4 => y =192/4² = 12 <------ 3..
4. The current I in an electric circuit varies inversely with the resistance R. If a current of 50 amperes is produced by a resistance of 6 ohms, what current will be produced by a resistance of 2 ohms?
V=iR = 50*6=300V, => 300V/2 ohms = 150A <------- 4....Show more

y = kx for some k
12 = k(16)
k = 3/4
When y = 15,
15 = 3x/4
60 = 3x
x = 20

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2/
y = k/x , and you can continue
3/
y=k/x^2
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