去括号,并合并同类项:(1)2n-(2-n)+(6n-2) (2)a+3(5a-2b)-2(3a-b)

问题描述:

去括号,并合并同类项:(1)2n-(2-n)+(6n-2) (2)a+3(5a-2b)-2(3a-b)

(1)2n-(2-n)+(6n-2) (2)a+3(5a-2b)-2(3a-b)
=2n-2+n+6n-2
=9n-4
(2)a+3(5a-2b)-2(3a-b)
=a+15a-6b-6a+2b
=10a-4b

1.9N-4
2.10a-4B

(1)2n-(2-n)+(6n-2)
=2n-2+n+6n-2
=9n-4
(2)a+3(5a-2b)-2(3a-b)
=a+15a-6b-6a+2b
=(1+15-6)a-6b+2b
=10a-4b

(1)2n-(2-n)+(6n-2)
=2n-2+n+6n-2
=(2+1+6)n-2-2
=9n-4
(2)a+3(5a-2b)-2(3a-b)
=a+15a-6b-6a+2b
=(1+15-6)a-6b+2b
=10a-4b