Is the following an algebraic expression: 18r + (r ÷ 8) - 13

Pelle's sister is three years older than pelle the father is 5 times as old as pelle the mother was 28 when the sister was born altogether they are 98 years old how old is pelle?

Identify a1 and r for the geometric sequence an= -256(-1/4) n-1

17 in long 1.3 ft wide and 8in high what is the volume