We have,
(i) ax + bx + ay + by = (ax + bx) + (ay + by) [Grouping the terms]
= (a + b)x + (a + b)y
= (a + b) (x + y) [Taking (a + b) common]
(ii) ax2+by2+bx2+ay2=ax2+bx2+ay2+by2 [Re-arranging the terms]
=(a+b)x2+(a+b)y2=(a+b)(x2+y2) [Taking (a + b) common]
(iii) a2+bc+ab+ac=(a2+ab)+(ac+bc) [Re-grouping the terms]
=a(a+b)+(a+b)c=(a+b)(a+c) [Taking (a + b) common]
(iv)ax–ay+bx–by=a(x–y)+b(x–y)
=(a+b)(x–y) [Taking (x – y) common]