• Best of luck to the class of 2024 for their HSC exams. You got this!
    Let us know your thoughts on the HSC exams here
  • YOU can help the next generation of students in the community!
    Share your trial papers and notes on our Notes & Resources page
MedVision ad

3u inequality questions, please help!!! (1 Viewer)

abdullion

New Member
Joined
Mar 18, 2015
Messages
12
Gender
Male
HSC
2016
Show full working out, please. It would be very helpful.

1. 1/5x^2-2x-7 < 5/13
2. 1 < 4x-4/2x+3 < 3
 
Last edited:

FrankXie

Active Member
Joined
Oct 17, 2014
Messages
330
Location
Parramatta, NSW
Gender
Male
HSC
N/A
Uni Grad
2004
when you have a fraction and don't use latex, you'd better add brackets to avoid confusing
 

Feynman

Active Member
Joined
May 12, 2014
Messages
216
Gender
Male
HSC
2016
For 1, just factor the denominator and multiply both sides by the whole thing squared. Then just deal with the algebra and you'll get (5x-7)(x+1)(5x-8)(5x+6) > 0. Find the roots and plot them on a graph, then sketch the polynomial. Reading the solutions you should get x < -6/5, -1 < x < 7/5 and x > 8/5.

For 2, break it down to two inequalities:

1 < 4x-4/2x+3 and 4x-4/2x+3 < 3

Do these normally and graph them on number planes reading the solutions. Then apply the solutions that satisfy BOTH inequalities. It should be x < -13/2 and x > 7/2.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top