When simplifying the quadratic formula to solve the equation x^2+6x-55=0, the number under the radical sign will be:A)-184B)232C)256

Mathematics · Middle School · Tue Nov 03 2020

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Given the equation:

x^2 + 6x - 55 = 0

a = 1

b = 6

c = -55

Simplify the quadratic equation, and determine the number under the radical sign.

Solution:
The Quadratic formula:

x = −b ± √(b^2 − 4ac)/2a

is used to solve quadratic equations where a ≠ 0, in the form
ax^2+bx+c=0

When b^2−4ac=0 there is one real root.

When b^2−4ac>0 there are two real roots.

When b^2−4ac<0 there are no real roots, only a complex number.

Substitute the given values of a, b and c to the quadratic formula.

x = −b ± √(b^2 − 4ac)/2a

x = −(6) ± √((6)^2 − 4(1)(-55))/2(1)

x = −6 ± √(36 + 220)/2

x = −6 ± √(256)/2

The number inside the radical sign is 256.

Final answer:

c. 256