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What is the discriminant of $(x - 2) (x + 5) = 8$ ?

Class 10The Quadratic FormulaAlgebra — Quadratics

A81
B49
C-63
D9

Step-by-Step Solution

Standard form first:

x^{2} + 3 x - 10 = 8 \Rightarrow x^{2} + 3 x - 18 = 0. D = 9 - 4 (1) (- 18) = 9 + 72 = 81

. (Forgetting to move the 8 across gives 49; the roots are

\frac{- 3 \pm 9}{2} = 3

or -6.)

Answer: A) 81

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