How do you solve #x^2-20=0# using the quadratic formula?

1 Answer
Patrick H.
Jul 25, 2016

Substitute the variables for the numbers in the equation to get your answer, #(+-4sqrt(5))/(2)#.

Explanation:

The quadratic formula is this: #(-b+-sqrt(b^2-4ac))/(2a)#. In the case of our equation, a=1, b=0, and c=-20. The equation now looks like this: #(-0+-sqrt(0^2-4(1)(-20)))/(2(1))#. We now simplify the equation to get #(+-sqrt(80))/(2)#. 80 is not a square root, but we can simplify this even further. 16 is a square root and a factor of 80. We now get #(+-4sqrt(5))/(2)#. This is our answer.

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