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QUARTER 1 MODULE 2
LESSON 1
NATURE OF ROOTS OF
QUADRATIC EQUATION
Nature of Roots of Quadratic Equation
Discriminant
• It is the number being
used to describe the
nature of roots of a
quadratic equation.
Formula:
d = b2 – 4ac
provided that the
equation is in standard
form.
discriminant Nature of Roots
d > 0
d is a perfect
square
Two real, rational and
unequal roots
d is not a
perfect
square
Two real, irrational and
unequal roots
d = 0 One real and rational root.
d < 0 No real root
discriminant Nature of Roots
d > 0
d is a
perfect
square
• Two real, rational and
unequal roots
d is not a
perfect
square
• Two real, irrational and
unequal roots
d = 0 • One real and rational root.
d < 0 • No real root
Remember: Equation must be in standard form Example 1: Describe the nature of roots
of 3t2 + 5t = 2
Solution:
3t2 + 5t = 2
3t2 + 5t – 2 = 0
a = 3, b = 5, c = –2
d = b2 – 4ac
d = (5)2 – 4(3)(–2)
d = 25 + 24
d = 49
Nature of Roots:
Two real, rational and unequal roots
Remember: Equation must be in standard form Example 2: Compute for the discriminant
of 9x2 – 12x + 4 = 0.
Solution:
9x2 – 12x + 4 = 0
a = 9, b = –12, c = 4
d = b2 – 4ac
d = (–12)2 – 4(9)(4)
d = 144 – 144
d = 0
Nature of Roots:
One real and rational root.
discriminant Nature of Roots
d > 0
d is a
perfect
square
• Two real, rational and
unequal roots
d is not a
perfect
square
• Two real, irrational and
unequal roots
d = 0 • One real and rational root.
d < 0 • No real root
Remember: Equation must be in standard form Example 3: What is the nature of roots of
h2 = 16 – 3h
Solution:
h2 = 16 – 3h
h2 + 3h – 16 = 0
a = 1, b = 3, c = –16
d = b2 – 4ac
d = (3)2 – 4(1)(–16)
d = 9 + 64
d = 73
Nature of Roots:
Two real, irrational and unequal roots
discriminant Nature of Roots
d > 0
d is a
perfect
square
• Two real, rational and
unequal roots
d is not a
perfect
square
• Two real, irrational and
unequal roots
d = 0 • One real and rational root.
d < 0 • No real root
Remember: Equation must be in standard form Example 4: Describe the nature of roots
of the equation 4k2 + 6k + 3 = 0
Solution:
4k2 + 6k + 3 = 0
a = 4, b = 6, c = 3
d = b2 – 4ac
d = (6)2 – 4(4)(3)
d = 36 – 48
d = –12
Nature of Roots:
No real root
discriminant Nature of Roots
d > 0
d is a
perfect
square
• Two real, rational and
unequal roots
d is not a
perfect
square
• Two real, irrational and
unequal roots
d = 0 • One real and rational root.
d < 0 • No real root
Remember: Equation must be in standard form Example 5: Determine the nature of roots
of the equation 3x2 + 11x + 8 = 0
Solution:
3x2 + 11x + 8 = 0
a = 3, b = 11, c = 8
d = b2 – 4ac
d = (11)2 – 4(3)(8)
d = 121 – 96
d = 25
Nature of Roots:
Two real, rational and unequal roots
discriminant Nature of Roots
d > 0
d is a
perfect
square
• Two real, rational and
unequal roots
d is not a
perfect
square
• Two real, irrational and
unequal roots
d = 0 • One real and rational root.
d < 0 • No real root
Answer Activity 1.3: What’s More? on
page 6 of your Quarter 1 Module 2
Thank you.
Nature of Roots of Quadratic Equation.pptx
Nature of Roots of Quadratic Equation.pptx
Nature of Roots of Quadratic Equation.pptx