First, eliminate the parenthesis by multiplying each term within the parenthesis by the term outside the parenthesis:
#color(red)(2j)(7j^2k^2 + jk^2 + 5k) - color(blue)(9k)(-2j^2k^2 + 2k^2 + 3j) =>#
#(color(red)(2j) xx 7j^2k^2) + (color(red)(2j) xx jk^2) + (color(red)(2j) xx 5k) + (-color(blue)(9k) xx -2j^2k^2) + (-color(blue)(9k) xx 2k^2) + (-color(blue)(9k) xx 3j) =>#
#14j^3k^2 + 2j^2k^2 + 10jk + 18j^2k^3 + (-18k^3) + (-27jk) =>#
#14j^3k^2 + 2j^2k^2 + 10jk + 18j^2k^3 - 18k^3 - 27jk#
Next, group and combine like terms:
#14j^3k^2 + 2j^2k^2 + 10jk - 27jk + 18j^2k^3 - 18k^3#
#14j^3k^2 + 2j^2k^2 + (10 - 27)jk + 18j^2k^3 - 18k^3#
#14j^3k^2 + 2j^2k^2 + (-17)jk + 18j^2k^3 - 18k^3#
#14j^3k^2 + 2j^2k^2 - 17jk + 18j^2k^3 - 18k^3#
