Question

Factorise using the grouping method :
m (x - 3y)² + n (3y - x) + 5x - 15y

Answer 1

m (x - 3y)² + n (3y - x) + 5x - 15y
= m (x - 3y)² - n (x - 3y) + 5(x - 3y)     
[Taking (x - 3y) common from all the three terms]
= (x - 3y) [m(x - 3y) - n + 5]
= (x - 3y)(mx - 3my - n + 5)