Solve `x^2-4x-4=0` 



1 Answer | Add Yours

lfryerda's profile pic

Posted on (Answer #1)

To solve this equation, we cannot factor it using integers or rational values, so instead we need to use the quadratic formula.

For the quadratic equation `ax^2+bx+c=0` , the quadratic formula is


In this case, a=1, b=-4 and c=-4, so the solutions to the equation are

`x={4+-sqrt{16-4(-4)}}/2`   simplify the square root

`={4+-sqrt32}/2`  simplify the radical


`={4+-4sqrt2}/2`   cancel common factor of 2 in numerator and denominator


The solutions of the equation are `x=2+2sqrt2` and `x=2-sqrt2` .

We’ve answered 288,191 questions. We can answer yours, too.

Ask a question