SOLUTION: Solve x^2 + 7x -2 = 0 And, then find the x-intercepts of f(x) = x^2 + 7x - 2. I appreciate the help, I am struggling with these problems and they do not come from a textbook.

Question 130767: Solve x^2 + 7x -2 = 0
And, then find the x-intercepts of f(x) = x^2 + 7x - 2.
I appreciate the help, I am struggling with these problems and they do not come from a textbook.
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
# 1

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=7, and c=-2

Square 7 to get 49

Multiply to get

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

Multiply 2 and 1 to get 2

So now the expression breaks down into two parts

or

So these expressions approximate to

or

So our solutions are:
or

Notice when we graph , we get:

when we use the root finder feature on a calculator, we find that and .So this verifies our answer

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