I am assuming you want to solve for m in each case
8n = -3m + 1
8(-2) = -3m + 1
-16 = -3m + 1
-3m = -17
m = 
8(2) = -3m + 1
16 = -3m + 1
-3m = 15
m = -5
8(4) = -3m + 1
32 = -3m + 1
-3m = 31
m = 
Trig ratios can only be used on right triangles with acute measures.
If given an angle and there are adjacent and opposite sides, then use tan(opposite/adjacent)
If given an angle and there is an adjacent side and a hypotenuse, then use cosine(adjacent/hypotenuse)
If given an angle and there is an opposite and adjacent side, then use sin(opposite/hypotenuse)
A common mnemonic device used to memorize the trig rules is SOH-CAH-TOA
A(r)=3.14r^2, when r=5
A(5)=3.14(5^2)
A(5)=3.14(25)
A(5)=78.5 u^2
-4/3 x (-3/4)x > -4/3 x (-6)
x > 4 x 2
x > 8