if theres one thing i really cant do its inequalities. can you guys help me out with some problems which all need to be shown in interval notation,
thanks
1) 2x squared+5x-3<0
2) x squared + 6x +9>0
- (that minus is below the greater than sign)
3) x squared - 49 < 0
-(same with this one to)
To learn, in general, how to solve quadratic inequalities, try some online lessons.
Long story short: Find the zeroes (which are where the graph crosses the x-axis). These zeroes will divide the number line into intervals. Once you've found these intervals, consider the graph.
For right-side-up parabolas (that is, for positive quadratics), the graph is below the x-axis (so the quadratic is negative) between the zeroes, and above the x-axis "on the ends" (so the quadratic is positive).
For upside-down parabolas (that is, for negative quadratics), the graph goes the other way 'round.
Using the zeroes and what you know about the graphs, pick the appropriate solution intervals.