How do you solve x^2 + 10x + 25 = 0 using the quadratic formula?

2 Answers
May 22, 2017

x = -5

Explanation:

The quadratic formula states that:

x = (-b+-sqrt(b^2-4ac))/(2a)

Where ax^2+bx+c=0.

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In this case, a = 1, b=10, and c=25. Now all we have to do is plug these values into the quadratic formula and simplify it.

x = (-b+-sqrt(b^2-4ac))/(2a)

x = (-10+-sqrt(10^2-4(1)(25)))/(2(1))

x = (-10+-sqrt(100-100))/2

x = (-10+-0)/2

Since adding or subtracting 0 wouldn't change the answer at all, we actually only have a single solution instead of 2 solutions.

x = (-10)/2 = -5

Final Answer

May 22, 2017

Double root at x = - 5

Explanation:

y = x^2 + 10x + 25 = 0
D = b^2 - 4ac = 100 - 100 = 0
Since D = 0, there is a double root at:
x = -b/(2a) = -10/2 = - 5