SOLUTION: 6. Solve using the quadratic formula: x^2 � 5x � 1 = -7

Question 132984This question is from textbook intermediate algebra
: 6. Solve using the quadratic formula:
x^2 � 5x � 1 = -7
This question is from textbook intermediate algebra

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

Start with the given equation

Add 7 to both sides.

Combine like terms

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=-5, and c=6

Negate -5 to get 5

Square -5 to get 25 (note: remember when you square -5, 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

Lets look at the first part:

Add the terms in the numerator
Divide

So one answer is

Now lets look at the second part:

Subtract the terms in the numerator
Divide

So another answer is

So our solutions are:
or

Notice when we graph , we get:

and we can see that the roots are and . This verifies our answer

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