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The quadratic equation whose roots are 3 and −5 is:

Competition practiceAlgebra

A $x^{2} - 2 x - 15 = 0$
B $x^{2} + 2 x + 15 = 0$
C $x^{2} - 2 x + 15 = 0$
D $x^{2} + 2 x - 15 = 0$

Step-by-Step Solution

Sum of roots =

3 + (- 5) = - 2

and product =

3 \times (- 5) = - 15

. The equation is

x^{2}

− (sum)

x

+ product = 0, i.e.

x^{2} + 2 x - 15 = 0

.

Answer: D)

x^{2} + 2 x - 15 = 0

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