Posted by Allison A on Tuesday, November 22, 2011 at 10:40pm.
Solve by completing the square
x^2+4x21=0
Help how do I do this???

Math  Fizzylicous, Tuesday, November 22, 2011 at 10:48pm
For this go on to the website discovery education. Then go under students and click math. And then where it says step by step math in green, click on trigonmetry and calculus. I forgot what area of math this is but choose from one of the items. And jot it in the box search thing and when you press enter it gives you the answer with a wonderful explanation on how to get there. I've used it for math a couple of times.

Math  Reiny, Wednesday, November 23, 2011 at 12:43am
x^2+4x21=0
x^2+4x = 21
take half the middle term coefficient, square it, then add it to both sides
x^2 + 4x + 4 = 21 + 4
(x+2)^2 = 25
x+2 = ± √25 = ± 5
x = 2 ± 5
x = 3 or 7
Answer This Question
Related Questions
 Math (Quadratics)  3. Solve for x in 8x^2 + 2x  4 = 0 I have tried factoring, ...
 Algebra 2  Solve by completing the square. a²  2√(3a) + 2 = 0 Solve for ...
 Algebra  Which of the following statements is true? A. Any quadratic equation ...
 math,correction  Is this correct now. Problem #1 solve by completing the square...
 maths  Consider the equation x(square) + 4px + 2q = 0 where p and q are real ...
 Math  Hi everyone. Would someone be able to help me with this problems? I know ...
 Algebra 2  Completing the square method allows you to solve any quadratic ...
 math  1. solve by using the quadratic formula. 5x^2+x=3 2. solve by completing ...
 math  i need to solve this equation by completing the square: x^214x+1=0 i don...
 math 10  by completing the square method solve the equation. x^22x1 can u ...
More Related Questions