Find the range of values of x for which: x^2 + 3x + 2 < 0

If you were to factorise this quadratic to find out its roots, you would get:

(x+1)(x+2)

which gives us roots of -1 and -2.

Remember that roots are where the graph crosses the x-axis, and are found by setting the factorised quadratic equal to zero.

(x+1)(x+2) = 0

Next you plot the graph. Notice that it is a U shaped graph since the co-efficient of xis positive.

Between -1 and -2, the graph is below the x-axis ( y < 0 ) and > -1 and < -2 the graph is above the x-axis ( y > 0 ).

The question is asking us for the range of x values where this graph is < 0, which is to say it is below the x-axis. We can see from our plot that the this range is -2 < x < -1.

TN
Answered by Thomas N. Maths tutor

4922 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How do I find the equation of a straight line from a graph?


a)Rearrange the folowing to make m the subject; 4(m-2) = t(5m+3)


Billy wants to buy 10kg of the same oranges. Type A comes in bags of 1.25 kg and costs £1.50. Type B comes in bags of 5kg and used to cost £6.60 but are now 15% off. Which type is more worth it for Billy and how much does it cost?


If a curve has equation y=(4/3)x^3-2x^2-24x+16, find dy/dx and find the coordinates of the turning points.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences