Tuesday

January 27, 2015

January 27, 2015

Posted by **Vilma** on Sunday, June 17, 2012 at 7:38pm.

What three techniques can be used to solve a quadratic equation? Demonstrate these techniques on the equation:

2x² + 3x + 1 = 0

- Algebra -
**Reiny**, Sunday, June 17, 2012 at 9:00pm1. Factoring (works only in special cases)

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

2x+1=0 or x+1=0

x = -1/2 or x = -1

2. completing the square, works all the time

(I use this method when the coefficient of the square term is 1 and the middle term is even)

divide by 2

x^2 + (3/2)x = -1/2

take 1/2 the coefficient of the middle term, square it and add it to both sides

x^2 + (3/2)x**+ 9/16**= -1/2**+ 9/16**

(x+ 3/4)^2 = 1/16

take √ of both sides

x+3/4 = ± 1/4

x = -3/4 ± 1/4

x = -1/2 or x = -1

3. The quadratic formula, works all the time.

x = (-3 ± √(9-4(2)(1))/4

= (-3 ±√1)/4

= -1/2 or -1

**Answer this Question**

**Related Questions**

Algebra - I was given this answers to a problems I solved but I do not ...

Algebra - I was given this answers to a problems I solved but I do not ...

algebra - Solve the linear equation using any technique you have learned. Name ...

ALGEBRA 2 - Factor the given expression. Then use the zero product rule and the ...

ALGEBRA 2 - Factor the given expression. Then use the zero product rule and the ...

algebra - which quadratic formula would be used to solve the following quadratic...

math algebra - Factor the given expression. Then use the zero product rule and ...

math algebra - Factor the given expression. Then use the zero product rule and ...

math algebra - Factor the given expression. Then use the zero product rule and ...

overview of teaching techniques - which technique is used after a student gives ...