Commutative property of addition
Hey there!
The answer to your question is a = s - b - C/2
<u>To solve for "a", we must get "a" on it's own side of the equal sign.</u> We can first subtract "s" from both sides:
<em>0 = a + b + C/2 - s</em>
Then, we can subtract a from both sides:
<em>-a = b + C/2 - s</em>
Finally, we divide both sides by -1, so a is by itself.
<em>a = -b - C/2 + s</em>
And we can rearrange it to the standard form:
a = s - b - C/2
Good luck, and hope it helped! Have a great day!
Answer:
Part a)
Part b) 
Part c) (s+t) lie on Quadrant IV
Step-by-step explanation:
[Part a) Find sin(s+t)
we know that

step 1
Find sin(s)

we have

substitute




---> is positive because s lie on II Quadrant
step 2
Find cos(t)

we have

substitute




is negative because t lie on II Quadrant
step 3
Find sin(s+t)

we have



substitute the values



Part b) Find tan(s+t)
we know that
tex]tan(s + t) = (tan(s) + tan(t))/(1 - tan(s)tan(t))[/tex]
we have



step 1
Find tan(s)

substitute

step 2
Find tan(t)

substitute

step 3
Find tan(s+t)

substitute the values




Part c) Quadrant of s+t
we know that
----> (s+t) could be in III or IV quadrant
----> (s+t) could be in III or IV quadrant
Find the value of cos(s+t)

we have



substitute



we have that
-----> (s+t) could be in I or IV quadrant
----> (s+t) could be in III or IV quadrant
----> (s+t) could be in III or IV quadrant
therefore
(s+t) lie on Quadrant IV
The first question I think it’s A because 1.13 is larger than 1.2
I hope this helps