Răspuns :
Răspuns:
Explicație pas cu pas:
(3-2a)²-(4a+1)²+(4a-5)(4a+5)=
9-12a+4a²-16a²-8a-1+16a²-25=
4a²-20a-17
(3-2a)²-(4a+1)²+(4a-5)(4a+5)=?
(a-b)²=a²-2ab+b² , (3-2a)²=9-12a+4a²
(a+b)²=a²+2ab+b² , (4a+1)²=16a²+8a+1
(a-b)(a+b)=a²-b² , (4a-5)4a+5)=16a²-25
9-12a+4a²-16a²-8a-1+ 16a²-25= 4a²-20a-17