Question 1097892
z <s>is partly constant and partly</s> varies <s>directly</s> 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=(90-59)/(11-8)=31/3}}}


{{{b=z-mx}}}
{{{b=90-11(31/3)}}}
{{{b=270/3-11*31/3}}}
{{{b=-71/3}}}


{{{z=(31/3)x-71/3}}}
If this does not give the result or answer you expect, then maybe you should explain better "partly constant and partly varies directly".