x(5x+2)<3?

x(5x+2) < 3
5x² + 2x - 3 < 0
(5x-3)(x+1) < 0
-1 < x < 3/5

x(5x+2)<3
5x^2 +2x-3<0
(5x-3)(x+1)<0
x+1>0 and 5x-3<0
x>-1 and x<3/5

x(5x+2)<3
5x^(2)+2x-3<0
(x-0.6)(x+1)<0
x<0.6 or x<-1(中學)
大專:
(x-0.6)(x+1)<0
x<0.6or x>-1
-1<x<0.6

x(5x+2) < 3 5x² + 2x - 3 < 0 (5x-3)(x+1) < 0 -1 < x < 3/5

x(5x+2) < 3
5x² + 2x - 3 < 0
(5x-3)(x+1) < 0
-1 < x < 3/5

x(5x+2) < 3
5x² + 2x - 3 < 0
(5x-3)(x+1) < 0
-1 < x < 3/5

x(5x+2) < 3
5x² + 2x - 3 < 0
(5x-3)(x+1) < 0
( 5x-3 < 0 and x+1 >0 ) or ( 5x-3 > 0 and x+1 <0 )
( 5x < 3 and x > -1 ) or (5x > 3 and x < -1 )
( x < 3/5 and x > -1 ) or ( x > 3/5 and x < -1 ) (rejected)
i.e. x < 3/5 and x > -1
∴ -1 < x < 3/5
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Note : -
慈信 's solution is in a way correct.
However, marks will be deducted as the solution would be classfied as INCOMPLETE.

Reason：
In between " (5x-3)(x+1) < 0 " and " -1 < x < 3/5 "，
a few steps are missing, namely ：
( 5x-3 < 0 and x+1 >0 ) or ( 5x-3 > 0 and x+1 <0 )
( 5x < 3 and x > -1 ) or (5x > 3 and x < -1 )
( x < 3/5 and x > -1 ) or ( x > 3/5 and x < -1 ) (rejected)
i.e. x < 3/5 and x > -1
These steps are actually vital.