1) (х-0.2у)(х+0.2у)=х²-(0,2y)²=x²-0,04y²
2) 49a⁴-121b²=(7a²)²-(11b)²=(7a²-11b)(7a²+11b)
3) (8+5x⁴)²=8²+2*8*5x⁴+(5x⁴)²=64+80x⁴+25x⁸
4) 81a²-180a+100=(9a)²-2*9a*10+10²=(9a-10)²
5) 0,064m³+125n⁶=(0,4m)³+(5n²)³=(0,4m+5n²)(0,16m²-2mn²+25n⁴)
6) 9x²-2,89=(3x)²-(1,7)²=(3x-1,7)(3x+1,7)
7) (4x⁴-5y)(16x⁸+20x⁴y+25y²)=(4x⁴-5y) (4x⁴-5y)²= (4x⁴-5y)³=(4x⁴)³-3*(4x⁴)²*5y+3*4x⁴*(5y)²-(5y)³ =64x¹²-240x⁸y+300x⁴y²-125y³
8) (11+8a)²=121+176a+64a²
9) (9x⁴+6y³)(9x⁴-6y³)=81x⁸-36y⁶
10) 0,09x⁸-4,8x⁴y+64y²=(0,3x⁴)²-2*0,3x⁴*8y+(8y)²=(0,3x⁴-8y)