quadratic equation, check my answer?

[dlthompson81]

2x^2 = 3 - 4x
2x^2 + 4x - 3 = 0
-4 +- sqrt4^2 - 4 * 2 * -3 over 2 * 2
-4 +- sqrt 40 over 4
-4 +- 2 sqrt 10 over 4
here where i think i might be messing up, im not sure about dividing with squares
-1 +- (1/2) sqrt 10

is this right? if not where did i go wrong? thanks in advance

 

[wjm11]

2x^2 = 3 - 4x
2x^2 + 4x - 3 = 0
-4 +- sqrt4^2 - 4 * 2 * -3 over 2 * 2
-4 +- sqrt 40 over 4
-4 +- 2 sqrt 10 over 4
here where i think i might be messing up, im not sure about dividing with squares
-1 +- (1/2) sqrt 10

Your work is correct. Good job.

 

[Loren]

-4 +- 2 sqrt 10 over 4

\(\displaystyle x=\frac{-4\pm2\sqrt{10}}{4}=\frac{2(-2\pm\sqrt{10})}{4}=\frac{-2\pm\sqrt{10}}{2}\)

 

[Denis]

While doing the solving, I find it easier to use quadratic this way:
2ax = -b +- sqrt(b^2 - 4ac)
Do the right side work, then the division by 2a.
Get it?

 

[patricemathis23]

hello all,
i am hoping to get some similar help. I have trouble with word problems. here we go the area of trapezoid is 55 aquare feet. if the bases are 7 and 15, fing the altitude of the trapezoid. A=1/2H(B1 +B2).

can someone please give me hint on how to over come this one. thank you in advance!
patrice

 

[Mrspi]

hello all,
i am hoping to get some similar help. I have trouble with word problems. here we go the area of trapezoid is 55 aquare feet. if the bases are 7 and 15, fing the altitude of the trapezoid. A=1/2H(B1 +B2).

can someone please give me hint on how to over come this one. thank you in advance!
patrice

In the future, please start a NEW THREAD, rather than posting at the end of someone else's thread.

That said, "word problem????"

You are given a formula for the area of a trapezoid:

A = (1/2)*h*(b[sub:1d3pifs1]1[/sub:1d3pifs1] + b[sub:1d3pifs1]2[/sub:1d3pifs1])

"h" is the altitude
"b[sub:1d3pifs1]1[/sub:1d3pifs1]" and "b[sub:1d3pifs1]2[/sub:1d3pifs1]" are the two bases.

The WORDS in the problem simply tell you what the area is, and what the lengths of the two bases are. The area is 55 sq. ft. Substitute 55 for A. One base is 7 feet, and one base is 15 feet. Substitute 7 and 15 for b[sub:1d3pifs1]1[/sub:1d3pifs1] and b[sub:1d3pifs1]2[/sub:1d3pifs1]:

55 = (1/2)*h*(7 + 15)

55 = (1/2)*h*22
55 = (1/2)*22*h
Now...you finish it. Since the area is in square feet, and the lengths of the bases are given in feet, the unit for the height will also be feet.

 

[patricemathis23]

thank you soooooooo much. but i am new to the website. dont know how to get to that. t hank you for helping me.

 

[Denis]

thank you soooooooo much. but i am new to the website. dont know how to get to that.

Do you not see the button "NEWTOPIC" at top left ?