Answer:
tan(x-y) = -16/63
Explanation
Tan(x-y) if cscx=13/5 and coty=4/3
Given
coty = 4
1/tany = 4/3
Cross multiply
tan y = 3/4
Also since cscx = 13/5
1/sinx = 13/5
sinx = 5/13
Since sinx = opp/hyp
opp = 5
hyp = 13
Get the adjacent
hyp² = opp²+adj²
13² = 5²+adj²
adj² = 13² - 5²
adj² = 169 - 25
adj² = 144
adj = 12
cosx = adj/hyp
cosx = 12/13
tanx = sinx/cosx
tanx = (5/13)/(12/13)
tanx = 5/13 * 13/12
tan x = 5/12
tan(x-y) = tanx - tany/1+tanxtany
tan(x-y) = (5/12 - 3/4)/1+(5/12)(3/4)
tan(x-y) = (5-9/12)/1+5/16
tan(x-y) = -4/12/(21/16)
tan(x-y) = -1/3 * 16/21
tan(x-y) = -16/63