Answers

  • Brainly User
2015-10-24T19:39:25+08:00
Find the discriminant in the expression:  b² - 4ac
From a given quadratic equation ax² + bx + c = 0, substitute the values of a, b, and c to the discriminant formula.

If b² - 4ac = 0, the nature of the roots is one real root of multiciplicity 2.

If b² - 4ac > 0 and is a perfect square; there are two distinct real roots, which are rational.

If b² - 4ac > 0 but NOT perfect square, there are two distinct real roots, which is irrational.

If b² - 4ac < 0, there is no real root.

Example:
4x² - 2x = -3

Re-write to:
4x² - 2x + 3 = 0
a = 4;   b = -2;   c = 3

Discriminant = b² - 4ac
Discriminant =(-2)² - 4 (4)(3) 
Discriminant = 4 - 48 
Discriminant = - 44 

- 44 < 0   Therefore there is no real root.
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