In plain and short, nope, their bases must be the same in order for the exponents to be summed up, whilst keeping the same base.
I wrote it out on paper and uploaded the answer for you. Let me know if you have any questions.
Answer:
70 degrees
Opposite angles are equal to each other
Answer:
1. M > -7
2. y < -1
3. m < -12
4. k > -2
5. c > -9
Please let me know if you need me to explain these answers! :)