Notice that the 2 expressions have 2 common terms.
(r-s) is just (s-r) times (-1)
similarly
(t-s) is just (s-t) times (-1)
this means that :
(r-s) (t-s) + (s-r) (s-t)=-(s-r)[-(s-t)]+(s-r) (s-t)
the 2 minuses in the first multiplication cancel each other so we have:
-(s-r)[-(s-t)]+(s-r) (s-t)=(s-r) (s-t)+(s-r) (s-t)=2(s-r) (s-t)
Answer:
d)<span>2(s-r) (t-s) </span>
23 lines × 5 trees= 115 tree. or. 5 lines × 23 trees = 115 trees
Using the same numbers u started out with
Answer:
C
Step-by-step explanation:
note that sin x = cos(90 - x ) ← Cofunction identity
If x = 36 then 90 - x = 90 - 36 = 54
Hence sin 36° = cos 54° → C
