Evaluate the expression. 6(3+5)/4

I’m stuck on this i don’t understand.

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

21 type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar. the solution set of n2 - 14n = -45 is { (separate the solutions with a comma)