via the angle sum formula of sin
which proves the second choice
the third choice is wrong since for x=0,y=0 it will show that 2=1 which is incorrect
for the fourth one you can do some thing similar to choice one just expand the sum formula of sin and that should be true too
so
the first , the second and the fourth are all true
Answer:
Step-by-step explanation:
<em>I believe that the answer should be A. </em>
1st add 7 to both sides : 3z = 21, 2nd divide both sides with 3: z = 7
First you would have to find the third angle in the triangle which you would do by adding 63+61 and subtracting the resulting number from the total degrees in a triangle. From there, you would calculate x and y using the knowledge that angles on a line equal 180.
