Assuming both angles indicate a point on the unit circle in quadrant 1, which is described in polar coordinates as having a range of 0 to pi/2 or 0 to 90 degrees, the cosine of a value decreases as angle increases. Naturally, since cos t = 0.45 and cos w = 0.89, cos t < cos w, therefore t > w.
First One:
-5(3m+6)=-3(4m-2)
-15m-30 = -12m+6
-3m = 36
m = -12
Second:
-7(k+9)=9(k-5)-14k
-7k-63 = 9k-45-14k
-7k-63=-5k-45
-2k=18
k=-9