Please help me with this question, this is my 3 time posting.

Given f(x) = x − 7 and g(x) = x2 . find g(f( g(f(4))

Ricardo ran the 400 meter race 3 times his fastest time was 54.3 seconds his slowest time was 56.1 seconds if his average time was 55.0 seconds what was his time for the third race

The perimeter of a triangle is 69 cm. the first is 5 cm shorter than the second side. the third side is twice as long the first side. find the length of each side