1) m² -16m+ 64= (m-8)²
2)81+ m²+ 18m= m²+ 18m+ 81= (m+9)²
3) 25+ x² - 10x= x² -10x+ 25= (x-5)²
4)9x² - 24xy + 16y²= (3x- 4y)²
5)100x² +y²+ 20xy= (10x+y)²
6) 25x² -20x+ 4= (5x- 2)²
2.
25- x²= (5-x)(5+ x)
x² - a²= (x-a)(x+ a)
16- 49y²= (4- 7y)(4+ 7y)
4x² -1= (2x-1)(2x+ 1)
3.
1) 4- 4x + x²= (2- x)²
2) 10x- 25y= 5(2x -5y)
3) -16y² - 12y= -4y(4y+ 3)
4) k² -6,25= (k+ 2,5)(k-2,5)
4) b³ -125= (b-5)(b² + 5b+ 25)