Saturday

February 28, 2015

February 28, 2015

Posted by **Alicia** on Monday, August 10, 2009 at 1:04am.

x^2+6x+13 = 0

2x^2-5x-3 = 0

- Algebra -
**drwls**, Monday, August 10, 2009 at 1:26amIn the first problem, you want to have

x^2 + 6x + 9 on the left side, since that is the perfect square (x+3)^2.

You can make that happen by rewriting the equation as

(x+3)^2 = -4

x +3 = + or- 2i

x = -3 +/- 2i

(i is the square root of -1)

Now that you have seen how completing the square works, you should try the second one. I would factor out 2 first to make the perfect square simpler. Start with

x^2 -(5/2)x = 3/2 (a)

The perfect square that you need is

x -(5/2)x + 25/16 = [x -(5/4)]^2

So add 25/16 to both sides of Equation (a)and go from there.

**Answer this Question**

**Related Questions**

math - x^2=8x-9 solve by completing the square to obtain exact solutions

algebra help - I need help with this problem not understanding it. Give exact ...

Math/College Algebra - 1.)Complete the square to find all real solutions of ...

Algebra 1 Answer Evaluation - Solve x^2 -6x - 13 = 0 by completing the square. ...

Algebra - Which of the following statements is true? A. Any quadratic equation ...

Maths - Solve for x (exact solutions): sin x - sin 3x + sin 5x = 0 ¦Ð ¡Ü x...

calculus - Solve the equation by extracting square roots. List both the exact ...

pre-calculus - solve the logarithmic equation. be sure to reject any value of x ...

Math - Give the exact and approximate solutions to three decimal places. X^2-7x+...

Algebra - Use the quadratic formula to solve the equation. Give exact answers: ...