13/35 because you have to find the common denominator which would be 35 and in order to get 7 to 35 you have to multiply the whole thing by 5 making the fraction equal 15/35 and you have to multiply the other fraction by 7 making it 7/35 add the two together which would equal 22/35 so to make that 35/35 it would have to be 13/35
Answer:
Step-by-step explanation:

In exponent multiplication, if the bases are same then add the exponents.
A. 10
because 80 - 10 = 70 & 90 - 2(10) = 70