For the part 4.

Simplify the expression as follows.

X(2X + 5) > 12

2X2 + 5X - 12 > 0

2X2 + 8X - 3X - 12 > 0

2X(X + 4) - 3(X + 4) > 0

(2X - 3)(X + 4) > 0

Assume,

(2X - 3) = 0 and (X + 4) = 0

So, X = 1.5 and X = -4

Now you have to put them in number line and check in which area it is satisfied. It's like this,

if X < -4 then (2X - 3)(X + 4) > 0
if X > -4 and X < 1.5 then (2X - 3)(X + 4) < 0
if X > 1.5 then (2X - 3)(X + 4) > 0

Therefore, the answer is (X < -4) or (X > 1.5)

Now I think you can do the rest. If you want I'll do it part by part later. Just try it.