SOLUTION: Can someone please show me how this is done. The way I am doing it the teacher says is incorrect. x^2 - 4x

SOLUTION: Can someone please show me how this is done. The way I am doing it the teacher says is incorrect. x^2 - 4x - 60 = 0

Question 151224: Can someone please show me how this is done. The way I am doing it the teacher says is incorrect.
x^2 - 4x - 60 = 0

Found 2 solutions by jim_thompson5910, jojo14344:
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
Here are two ways to solve this problem

Method #1 Quadratic Formula (preferred method):

Start with the given equation.

Notice we have a quadratic equation in the form of where , , and

Let's use the quadratic formula to solve for x

Start with the quadratic formula

Plug in , , and

Negate to get .

Square to get .

Multiply to get

Rewrite as

Add to to get

Multiply and to get .

Take the square root of to get .

or Break up the expression.

or Combine like terms.

or Simplify.

So our answers are or

Method #2 Factoring:

Start with the given equation

Factor the left side (note: if you need help with factoring, check out this solver)

Now set each factor equal to zero:
or

or Now solve for x in each case

So our answers are

or

Notice if we graph we can see that the roots are and . So this visually verifies our answer.

Note: even though the factoring method may seem easier, it does not work for every quadratic.

Answer by jojo14344(1513) (Show Source): You can put this solution on YOUR website!
x^2 - 4x - 60 = 0
=} ---------------> its a perfect square
If you want quadratic formula its up to you,
, ,
=
*Plug the given and you'll get the same answer
Thank you,
Jojo
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