# Algebra 1 (Reiny)

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Find the roots of each quadratic polynomial.

1. x^2 + 2
2. x^2 - 6x - 7

• Algebra 1 (Reiny) -

1. x^2 = -2
x = +/- i sqrt 2 imaginary roots

2. x = [ 6 +/- sqrt (36+28) ] / 2
= 3 +/- 4
7 or -1
or just factor it
(x-7)(x+1) = 0

• Algebra 1 (Reiny) -

I'm sorry, but I don't understand. I haven't learned about this solving method yet. What are imaginary roots?

• Algebra 1 (Reiny) -

If you have not learned about imaginary roots then you have a typo in number 1
You can not solve
x^2 = -2
Unless you have had complex numbers.
You can do number two the second way I did it, by factoring.

• Algebra 1 (Reiny) -

I haven't learned to factor quadratic equations yet, either. In my current lesson, I'm learning to solve quadratic equations by graphing. However, I am struggling to grasp the concept. Thus, what is a simple way to find the roots of quadratic equations by graphing?

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