-9 = x + 4

Please Help

Astudent simplified a rational expression as shown.

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 square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base