Answer:
This is khan academy. I am pretty sure they have a video for this but whatever.
Step-by-step explanation:
So we are using sin, cosine, and tan. 3.4 is the hypotenuse. the side is X. The angle is 20 degrees. So, this is adjacent to hypotenuse. This means it is cosine.
3.4cos(20)= around 3.19
And thats that! let me know if this is wrong and I will try to fix it.
yes, it does not matter if the y is at the beginning or at the end. However, most teachers usually prefer to have the y at the beginning as it is easier to read.
Answer:

Step-by-step explanation:

Check if you can write an equation relating the term number to the actual value
n1=3
n2=10 = 3+7
n3= 17 = n2+7 = n1+7+7 = n1 +2*7
n4= 24 = n1+3*7
so you will notice a pattern
for the x-th term
n_x =3+(x-1)*7
the 50th term would be n_50 = 3+(50-1) * 7