36a⁴-25 = (6a²+5)(6a²-5)

216x³-1 = (6x-1)(36x²+6x+1)

100b²-140bx²+49x⁴ = (10b-7x²)(10b-7x²)

125b³+27 = (5b+3)(25b²-15b+9)

(5a-1/5)² = (5a-1/5)(5a-1/5) = 5a-1/5

(3a-5b²)(9a²+15ab²+25b⁴) = 3a(9a²+15ab²+25b⁴)-5b²(9a²+15ab²+25b⁴) = 27a³+45a²b²+75ab^4-45a²b²-75ab^4-125b^6 = 27a³-125b^6

(0,8x+5)(5-0,8x) = 50,8x + 55 - 50,8x - 0,8x5 = 4x + 25 - 4x - 4 = 21

(7x+0,4)² = (7x+0,4)(7x+0,4) = 49x²+7,4x+7,4x+0,16 = 49x²+14,8x+0,16

(6y+1)(36y²-6y+1) = 6y(36y²-6y+1)+1(36y²-6y+1) = 216y³-36y²+6y+36y²-6y+1 = 216y³+1

25x²+60xy+36y² = (5x+6y)(5x+6y) = (5x+6y)²