a2+5ab+6b2+a+3b
=a2+6ab+9b2+a+3b-ab-3b2
=(a+3b)^2+(a+3b)-b(a+3b)
=(a+3b+1-b)(a+3b)
=(a+2b+1)(a+3b)
a2+5ab+6b2+a+3b字母后面的是指数,因式分解
a2+5ab+6b2+a+3b
=a2+6ab+9b2+a+3b-ab-3b2
=(a+3b)^2+(a+3b)-b(a+3b)
=(a+3b+1-b)(a+3b)
=(a+2b+1)(a+3b)