SOLUTION: Please help with the the equation {{{ x^2-4x+1=0 }}} I understand a= 1 b=-4 c=1 and using {{{ b^2-4ac }}} Why is the the discriminant: {{{ 4^2-4*1*1 = 12 }}} and not

SOLUTION: Please help with the the equation {{{ x^2-4x+1=0 }}} I understand a= 1 b=-4 c=1 and using {{{ b^2-4ac }}} Why is the the discriminant: {{{ 4^2-411 = 12 }}} and not

Question 106068: Please help with the the equation
I understand a= 1 b=-4 c=1
and using
Why is the the discriminant:
and not
Shouldnt equal -4 not 4
Thanks

Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!

Solved by pluggable solver: Quadratic Formula

Let's use the quadratic formula to solve for x:

Starting with the general quadratic

the general solution using the quadratic equation is:

So lets solve ( notice , , and )

Plug in a=1, b=-4, and c=1

Negate -4 to get 4

Square -4 to get 16 (note: remember when you square -4, you must square the negative as well. This is because .)

Multiply to get

Combine like terms in the radicand (everything under the square root)

Simplify the square root (note: If you need help with simplifying the square root, check out this solver)

Multiply 2 and 1 to get 2

So now the expression breaks down into two parts

or

Now break up the fraction

or

Simplify

or

So the solutions are:

or

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