Factorise a(a-4)(a²-4a-1)-20
Answers
Answered by
1
Step-by-step explanation:
(a2 - 4a)(a2-4a-1)-20 =0
a2-4a-1-20=0
a2-(7-3)a-21=0
a2-7a+3a-21=0
a(a-7)+3(a-7)=0
(a+3)(a-7)=0
a-7=0
a=7
Similar questions