Question

Solve u^3 + 3u^2 > 10u

Answer 1

\[u ^{3} + 3u ^{2} -10u > 0\]\[u ( u ^{2} + 3u - 10) > 0\]\[u ( u + 5 ) ( u-2) >0\] For the product to be positive, all three should be positive or one positive and two others negative. So put all combinations and find out what the values of u are

Answer 2

what would that look like?

Answer 3

first option : u > 0 ; (u + 5) > 0; (u - 2) > 0 ; all positive
The other options keep one positive and the other two negative