Answer:
117649
Step-by-step explanation:
First lets evaluate the parts:
7^8 = 5764801
7^7 = 823543
7^6 = 117649
adding and subtracting these 3 values as stated in the expression results in 5058907 which when divided by 43 is 117649.
While there is probably a faster way to do this, this does work.