1. х²-9х=0
х(х-9)=0
х₁ = 0
х-9=0, х₂ = 9
2. (a+b)(a-b)(a⁴+a²b²+b⁴) = (a²-b²)(a⁴+a²b²+b⁴) = (a²)³-(b²)³ = a⁶-b⁶
3. (1/х - 1/3)(1/х + 3/4)=0
1/х - 1/3 = 0, 1/х = 1/3, х₁ = 3
1/х + 3/4 = 0, 1/х = -3/4, х₂ = -4/3 = - 1 1/3
4. х⁴+ух³-х-у = х³(х+у)-(х+у) = (х+у)(х³-1) = (х+у)(х-1)(х²+х+1)