SOLUTION: z is partly constant and partly varies directly as x. When x=8, z=59. when x=11, z=80. Find the value of z when x=5.

Algebra ->  Proportions  -> Lessons -> SOLUTION: z is partly constant and partly varies directly as x. When x=8, z=59. when x=11, z=80. Find the value of z when x=5.      Log On


   

Question 1097892: z is partly constant and partly varies directly as x. When x=8, z=59. when x=11, z=80. Find the value of z when x=5.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
z is partly constant and partly varies directly as x. When x=8, z=59. when x=11, z=80. Find the value of z when x=5.

You may have ordered pair as (x,z) and your described points are (8,59) and (11,90). You could find a relationship like z=mx+b.

m=%2890-59%29%2F%2811-8%29=31%2F3

b=z-mx
b=90-11%2831%2F3%29
b=270%2F3-11%2A31%2F3
b=-71%2F3

z=%2831%2F3%29x-71%2F3
If this does not give the result or answer you expect, then maybe you should explain better "partly constant and partly varies directly".