Hi

y varies directly as the square of x

a. Find the constant of proportionality if y=4 when x=3. What is x when yis 16?

  4 = k*9  k = 9/4    

  16 = 9/4*x*2

  64/9 = x^2     x = ± 8/3



b. if the constant of variation is 5/8, what is y when x=6? what i x when y= 90?

  y = (5/8)*36 = 22.5      90 = (5/8)x^2    x = ± 12 



c. find the constant of variation and the value of y when x=5 if y=2 when x=2

   2 = k*2^2   k = 2/4 = 1/2      y = (1/2)*25   y = 25/2  or 12.5 

 

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