Quadratics

Question 1

What is a monic quadratic?

Answer 1

A quadratic where the coefficient of x² is 1.

Question 2

If asked to solve using algebra, what should you do?

Answer 2

You must include evidence of factorising or using quadratic formula in your answers.

Question 3

If the questions does not ask you to solve using algebra, what should you do?

Answer 3

Use your calculator to solve the quadratic.

Question 4

What should you always make sure you do before solving a quadratic?

Answer 4

Make sure the quadratic = 0

Question 5

How do you complete the square if it’s a non monic quadratic?

Answer 5

Factorise out the coefficient of x²

Complete the square “inside the square”

Expand

Question 6

What is the discriminant of ax²+bx+c?

Answer 6

b²-4ac

Question 7

How many (if any) solutions do the following have:

1. b²-4ac > 0
2. b²-4ac = 0
3. b²-4ac < 0

Answer 7

1. Two distinct solutions
   (Positive discriminant)
2. One repeated solutions
   (Discriminant = 0)
3. No solutions
   (Negative discriminant)