10 times how many days and then add 84 dollars and make it equal 169 dollars So it would be 10d+84+h =169 then the six would go in for “d” like this 10(6)+84+h=169 because (h= harness cost) then you would multiply 10 times 6 witch is 60+84+h=169 then you would add 60+84 144+h=169 then u subtract 144 from both sides 144+h=169 -144 -144 h=25 the harness cost $25 I’ll explain more if u need just let me know