S=d/t so in this case it's 75/12 which is 6.25. Round it and you got 6 miles per hour.
Since there are no specific requirements given other than expression written using exponents, I am just going to give some examples.
1. 5x^2 - 3
2. 8^5 - 15x + 7
3. 15x^10 - 8x^7 + 16x^5 + 17^3 - 4^2 +13x - 2
Q.What is the equivalent expression of 3p+12m+8
A.12m+3p+8
Hope this helps:)