Question

(a-2)(a-3)+5a-42

Answer 1

(a-2)(a-3)+5a-42
=a²-5a+6+5a-42
=a²-36

【学习宝典】团队为您答题。有不明白的可以追问！

追问

a²-5a+6+5a-42
两个5a 和6怎么来的

追答

(a-2)(a-3)=a²-3a-2a+6=a²-5a+6

Answer 2

(a-2)(a-3)+5a-42=a²-5a+6+5a-42=a²-36=(a+6)(a-6)

追问

a²-5a+6+5a-42
两个5a 和6怎么来的

追答

(a-2)(a-3)=a平方-5a+6
再加后面的5a-42
(a-2)(a-3)+5a-42=a²-5a+6+5a-42=a²-36=(a+6)(a-6)

Answer 3

a²-6-42=a²-36=(a+6)(a-6)

Answer 4

=a^2-5a+6+5a-42=a^2-36