1) 3x-ay+bz
3(5c³+2) -3c(5c² -c+15)+11c³(5c-1)=
=15c³+6-15c³+3c²-45c+11c⁴-11c³=
=11c⁴ - 11c³ +3c² -45c +6
2) 9ab(10a² -b²) +10ab(b²-9a²) =
=90a³b - 9ab³ + 10ab³ -90a³b =
=ab³
10 * (-5)³=10*(-125)= -1250
3) (5 ¹/₆ + 7 ¹/₇) : 517=
=(³¹/₆ + ⁵⁰/₇) : 517=
= (31*7 + 50*6) : 517 =
42
= 517 * 1 = 1
42 517 42