1. a) 5x^3 -45x =5x(x² -9) =5x(x -3)(x +3)
b) 13x² +26xy +13y² =13(x² +2xy +y²) =13(x +y)² =13(x +y)(x +y)
в) m^6 -64 =(m^3)² -8² =(m^3 -8)(m^3+8) =(m -2)(m² +2m +4)(m+2)(m²-2m+4) =(m-2)(m+2)(m²+2m+4)(m²-2m+4)
2. 7x^3 -28x =0
7x(x² -4) =0
7x =0, x =0
x² -4 =0, (x-2)(x+2) =0
x=2, x= -2
3. a² -8a -33 =(a -4)² -49 =(a -4 -7)(a -4 +7) =(a -11)(a +3)