Core 1 – discriminant

Yesterday we looked at solving inequalities. This topic is often combined with use of the discriminant. The discriminant (D = b2 – 4ac) tells you how many roots a quadratic of the form ax2 + bx + c = 0 has.

if

D > 0, there are two distinct and real roots

D = 0, there is one repeated root

D < 0, there are no real roots

 

Watch the video below and then try the exam questions

January 2006 question 4 – answers here

June 2013 question 7 – answer here

Most question though are harder than this, take a look through some of these videos and then try the exam question below.

January 2013 Question 8 – answer here

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