HELP ME ASAP 6TH GRADE MATH if you answer dis and me get good grade you will get a surprise

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

He ! a group of farmers planned to clean 80 acres of wheat per day to finish the work on schedule. right before the work started, they received a new piece of machinery that them clean 10 more acres per day than originally planned. as a result of increased productivity in the last day before the deadline they only had to clean 30 acres. how many acres of wheat did the group of farmers have to clean?

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.