Question

y varies jointly with p and q. When p = 7 and q = 2, y = 70. Find y when p = 8 and q = 4.

y = 120

y = 160

y = 200

y = 240

Answer 1

jointly means directly i'm guessing?

Answer 2

y = k*p*q since it is varying jointly

70 = 2*7*k
k = 5

y = 5*8*4 = 160 B

Answer 3

y varies inversely as three times x. When x = 6, y = 2. Find x when y = 12.

x = 1

x = 3

x = 6

x = 9

Answer 4

@Jhannybean yes, jointly means directly, i think they use jointly when there are two variables

Answer 5

okay.

Answer 6

classic examples of joint variation from physics would be force due to gravity or electrostatic attraction between two bodies

Answer 7

x=1

The equation of variation then is this:

y = 36/3x
y = 12/x
Above we canceled a factor of 3 in the numerator and denominator.

Now we can find x when y = 12:

y = 12/x
x = 12/y
x = 12/12
x = 1.

So when y = 12, x = 1.

Answer 8

Oh,makes more sense @whpalmer4

Answer 9

Solve –4x + 7 = x + 2

x = –1

x = 1

x = –3

x = 3

Answer 10

@jhannybean and as a bonus, at no extra charge, you get inverse variation with the square of the distance — call now, operators are standing by to take your order! :-)

Answer 11

@pamelasaucedo you shouldn't post unrelated questions in the same thread, open a new one.

Answer 12

@lopezking1 walk her through the steps and let her figure out the answer.

Answer 13

Move the - 4x over so it is 7 = 4x + x + 2

Answer 14

Then take the 2 over so it is 7 - 2 = 4x + x