SOLUTION: Write the function that models each relationship. Find z when x = 4 and y = 8. z varies directly with x and inversely with y. When x = 5 and y = 2, z = 10.

Algebra ->  Rational-functions -> SOLUTION: Write the function that models each relationship. Find z when x = 4 and y = 8. z varies directly with x and inversely with y. When x = 5 and y = 2, z = 10.      Log On


   

Question 1079483: Write the function that models each relationship. Find z when x = 4 and y = 8. z varies directly with x and inversely with y. When x = 5 and y = 2, z = 10.
Answer by MathLover1(20850) About Me  (Show Source):
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z varies directly with x and inversely with y

z+=+%28k%2Ax%29%2Fy...Solve for k using given data: when x+=+5 and y+=+2,+z+=+10

10+=+%28k%2A5%29%2F2

10%2A2+=+k%2A5

20%2F5+=+k

k=4

then z+=+4x%2Fy

Find z when x+=+4 and y+=+8:

z+=+%284%2A4%29%2F8

z+=+16%2F8

z+=+2