Simplify the following:
(i) (1.5x−4y)(1.5x+4y+3)
(ii) (x+y)(2x+y)+(x+2y)(x−y)
(iii) (a2+5)(b3+3)+5 [3 MARKS]
Application: 1 Mark each
(i) (1.5x−4y)(1.5x+4y+3)
2.25x2+6xy+4.5x−6xy−16y2−12y
⇒2.25x2−16y2+4.5x−12y
(ii) (x+y)(2x+y)+(x+2y)(x−y)
(2x2+xy+2xy+y2)+(x2+xy−2y2)
3x2+4xy−y2
(iii) (a2+5)(b3+3)+5
a2b3+3a2+5b3+15+5
⇒a2b3+3a2+5b3+20