(х+1)⁵ = (х+1)(х+1)(х+1)³ = (х²+2х+1)(х+1)(х+1)² = (х³+3х²+3х+1)(х+1)(х+1) = (х⁴+4х³+6х²+4х+1)(х+1) = х⁵+4х⁴+6х³+4х²+х+х⁴+4х³+6х²+4х+1 = х⁵+5х⁴+10х³+10х²+5х+1