Question 332724
(four-fifths x^3 +2x^2 - three-eights)-( two-fifths x^3 + 3x - five-eighths) = 
..
{{{((4/5)x^3+2x^2 -3/8)-((2/5)x^3+3x-5/8)}}}
..
{{{((4/5)x^3+2x^2 -3/8-(2/5)x^3-3x+5/8)}}}
group the common terms
..
{{{(4/5)x^3-(2/5)x^3+2x^2-3x-3/8+5/8)}}}
..
{{{(2/5)x^3+2x^2-3x+2/8)}}}