1) a(3a2 – 4b)+b(4a-a2)
2)c(c4-c3+c2)-(c4-c3+c2)
3)19-2(5x+4)=10

1) a(3a²-4b)+b(4a-a²)
3а³-4ab+4ab-a²b
3a³-a²b
2) c(c⁴-c³+c²)-(c⁴-c³+c²)
(c⁴-c³+c²)×(c-1)
c²(c²-c+1)(c-1)
3) 19-2(5x+4)=10
19-10x-8=10
11-10x=10
-10x=10-11
-10x=-1|÷(-10)
x=1/10