Answer:
(a)
(b) 
Step-by-step explanation:
It is given that
.
(a)
(b)
![[\because \sin x=\dfrac{1}{\csc x}]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%5Csin%20x%3D%5Cdfrac%7B1%7D%7B%5Ccsc%20x%7D%5D)

Therefore,
.
7r=-7/2
divide both sides by 7 to get r by itself
(7r)/(7) = (-7/2)/(7)
if you don't quite see it, think of multiplying both sides by 1/7 instead (its the same thing as dividing by 7)
(7r)*(1/7)=(-7/2)*(1/7)
r=-1/2
Answer:
x=4
Step-by-step explanation:
Consider ΔKLJ:
sinθ=opposite/hypotenuse
sin30=LJ/8√2
LJ=0.5*8√2=4√2
Consider ΔMLJ:
sinθ=opp/hyp
sin45=x/4√2
1/√2=x/4√2
4√2/√2=x
x=4