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September 20, 2014

September 20, 2014

Posted by **astrid** on Wednesday, April 2, 2008 at 10:08pm.

I guess the wall and the ladder form a right triangle.

- algebra -
**Reiny**, Wednesday, April 2, 2008 at 10:15pmyes, so solve

15^2 + x^2 = (2x+1)^2

- algebra -
**astrid**, Wednesday, April 2, 2008 at 10:31pmI tried that but it didnt give me a quadratic equation and thats what we've been studying.

- algebra -
**Reiny**, Wednesday, April 2, 2008 at 10:40pmwhy did you not get a quadratic?

15^2 + x^2 = (2x+1)^2

225 + x^2 = 4x^2 + 4x + 1

3x^2 + 4x - 224 = 0

see?

since you are studying quadratics I will let you finish it. (hint: 8 is a nice number)

- algebra -
**barb**, Wednesday, April 2, 2008 at 10:48pm2(3y)2(2x)

- algebra -
- algebra -
**Anonymous**, Wednesday, April 2, 2008 at 10:46pm? Just move all values to one side and leave the other side to zero and there's your quadratic formula.

Let x be the distance from the wall to the bottom of the ladder

Let 2x+1 be the length of the ladder

15^2 + x^2 = (2x+1)^2

4x^2 + 4x + 1 = 15^2 + x^2 I just expanded and switched the sides

3x^2 + 4x - 224 = 0

x^2 + 4x - 672 = 0 <-- bridge method is not in the NYC curriculum but I don't know about yours

(x+28)(x-24) = 0

(3x+28)(3x-24) = 0

(3x+28)(x-8) = 0

x = 8, -28/3(rej because its silly for the distance to be negative)

- algebra -
**Anonymous**, Wednesday, April 2, 2008 at 10:49pm? Just move all values to one side and leave the other side to zero and there's your quadratic *correction* equation.

- algebra -
- algebra -
**astrid**, Wednesday, April 2, 2008 at 10:53pmI get it now. I messed up on (2x+1)^2. I didn't simplify it right. Thank you guys so much.

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