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How do I solve the following quadratic equations?

0 votes

How do I solve step by step these three quadratic equations? 

1) x^2 + 8x = 0 


2) x^2 + 3x + 2 = 0 


3) Form a quadratic with the roots -1 and 2 


Thank you :)

asked May 4, 2014 in ALGEBRA 2 by anonymous

1 Answer

0 votes

1) The  quadratic equation is  x 2 + 8 = 0

x (x + 8) = 0

Aplly zero product property.

x  = 0 and x  + 8 = 0

 Solution x = 0 and  - 8.

2)    x 2 + 3x + 2 = 0

Factorise the above quadratic equation.

  x 2 + 2x  + x  + 2 = 0

x ( x + 2) + 1 ( x + 2) = 0

( + 2 ) (x  + 1) = 0

Aplly zero product property.

x  + 2 = 0 and x  + 1 = 0

 Solution x  = -2 and  -1.

3) Roots of quadratic equation x  = -1 and 2.

From the factor therom

When f (c ) = 0 then - c  is a factor of the polynomial.

(x  + 1) (x  - 2) = 0

2 + x - 2x - 2 = 0

x 2 - x - 2 = 0

Required quadratic equation is x 2 - x - 2 = 0.

answered May 5, 2014 by david Expert

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