1)(y-4)(y+6)=y2+6y-4y-24=y2+2y-24 2)(4a+1)(2a-3)=8a2-12a+2a-3=8a2-10a-3 3)(2y-b)(4y+3b)=8y2+6by-4by-3b2=8y2+2by-3b2 4)(a-3)(a2-5a+10)=a3-5a2+10a-3a2+15a-30=a3-8a2+25a-30