# polynomial equations - real roots

• March 11th 2010, 10:49 AM
polynomial equations - real roots
Determine the real roots of each equation

(5x^2+20)(3x^2-48) = 0

(x^2+1)(2x^2 - x - 13) = 0
• March 11th 2010, 11:40 AM
e^(i*pi)
Quote:

Determine the real roots of each equation

(5x^2+20)(3^2-48) = 0

(x^2+1)(2x^2 - x - 13) = 0

Possible typo in the first question? As it stands there are no real roots.

If, as I suspect, you mean $(5x^2+20)(3x^2-48)=0$. In this case ignore the first bracket.

Divide through by 3 and ignore the first brackets: $x^2-16=0$

This is a classic example using the difference of two squares.

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With the second one you can also ignore the first bracket as it has no real solutions