Question 1013406

{{{(5j - 9k)^2}}}

={{{(5j - 9k)(5j - 9k)}}}

={{{5j*5j - 9k*5j- 9k*5j- 9k*(- 9k)}}}

={{{25j^2 - 45kj- 45kj+ 81k^2}}}

={{{25j^2 - 90kj+ 81k^2}}}