更新1:
The answer sheet I have says that the answer is -4+/- the square root of 26 all over 10. I don't know how to get there.
10x^2+2x=1. I need the answer ASAP. Please?!?
2008-08-16 5:43 pm
I have to solve for x, but every time i plug it into the quadratic formula, i can't square root it because of negatives. Help please!
回答 (8)
2008-08-16 5:52 pm
✔ 最佳答案
10x^2+2x=110x^2+2x-1=0
-(2) +/- sqrt(2^2-(4)(10)(-1)/(2)(10)
-2 +/- sqrt(44)/(20)
(-2 + sqrt(44))/(20) and (-2+sqrt(44))/(20)
you can calculate the sqrt(44) and come up with two real answers
2008-08-18 3:43 am
10 x² + 2x - 1 = 0
x = [ - 2 ± â (4 + 40) ] / 20
x = [ - 2 ± â (44) ] / 20
x = [ - 2 ± 2â (11) ] / 20
x = [ - 1 ± â (11) ] / 10
x = [ - 2 ± â (4 + 40) ] / 20
x = [ - 2 ± â (44) ] / 20
x = [ - 2 ± 2â (11) ] / 20
x = [ - 1 ± â (11) ] / 10
2008-08-17 1:40 am
10x^2 + 2x = 1
10x^2 + 2x - 1 = 0
x = [-b 屉(b^2 - 4ac)]/2a
a = 10
b = 2
c = -1
x = [-2 屉(4 + 40)]/20
x = [-2 屉44]/20
x = [-2 ±6.63]/20 (approx.)
x = [-2 + 6.63]/20
x = [-2 + 6.63]/20
x = 4.63/20
x = 0.2315
x = [-2 - 6.63]/20
x = -8.63/20
x = -0.4315
â´ x â -0.4315 , 0.2315
10x^2 + 2x - 1 = 0
x = [-b 屉(b^2 - 4ac)]/2a
a = 10
b = 2
c = -1
x = [-2 屉(4 + 40)]/20
x = [-2 屉44]/20
x = [-2 ±6.63]/20 (approx.)
x = [-2 + 6.63]/20
x = [-2 + 6.63]/20
x = 4.63/20
x = 0.2315
x = [-2 - 6.63]/20
x = -8.63/20
x = -0.4315
â´ x â -0.4315 , 0.2315
參考: Square Root Calculator
http://www.math.com/students/calculators/source/square-root.htm
2008-08-17 1:17 am
10x^2+2x=1
x=-2+-sqt4+40/20
x=-2+-sqt44/20
x=-40+-sqt44
Either x=-40-sqt44 or x=-40+sqt44
x=-2+-sqt4+40/20
x=-2+-sqt44/20
x=-40+-sqt44
Either x=-40-sqt44 or x=-40+sqt44
2008-08-17 1:01 am
10x²+2x=1
10x²+2x-1=0
x=(-2屉(4-(-40))/20
x=(-2屉44)/20
x=(-2+ 2â11)/20
x=(-1+â11)/10
x=.23166
x=(-1-â11)/10
x=-.43166
This is the rigth answer
10x²+2x-1=0
x=(-2屉(4-(-40))/20
x=(-2屉44)/20
x=(-2+ 2â11)/20
x=(-1+â11)/10
x=.23166
x=(-1-â11)/10
x=-.43166
This is the rigth answer
2008-08-17 12:55 am
10x^2+2x-1=0
-2(+ or -)sqrt(44)/20
-2(+ or -)sqrt(44)/20
2008-08-17 12:54 am
Ax^2 +Bx+C=0
arranging the equation
10x^2+2x-1=0
A=10
B=2
C=-1
D=B^2-4AC
=4+40
=44square root of 44=6.63
( -1+6.63)/20 and ( -1- 6.63)/20
arranging the equation
10x^2+2x-1=0
A=10
B=2
C=-1
D=B^2-4AC
=4+40
=44square root of 44=6.63
( -1+6.63)/20 and ( -1- 6.63)/20
2008-08-17 12:51 am
Solve by completing the square:
10x^2 + 2x = 1 (divide both sides by 10)
x^2 + 1/5x = 1/10 (take half of 1/5, which is 1/10, and square it to 1/100, then add it to both sides)
x^2 + 1/5x + 1/100 = 1/10 + 1/100 (combine like terms)
x^2 + 1/5x + 1/100 = 11/100 (factor right side of equation)
(x + 1/10)(x + 1/10) = 11/100
(x + 1/10)^2 = 11/100 (square root both sides)
x + 1/10 = (sqrt11)/10 (subtract 1/10 from both sides)
ANSWER: x = (sqrt11)/10 - 1/10, (-sqrt11)/10 - 1/10
10x^2 + 2x = 1 (divide both sides by 10)
x^2 + 1/5x = 1/10 (take half of 1/5, which is 1/10, and square it to 1/100, then add it to both sides)
x^2 + 1/5x + 1/100 = 1/10 + 1/100 (combine like terms)
x^2 + 1/5x + 1/100 = 11/100 (factor right side of equation)
(x + 1/10)(x + 1/10) = 11/100
(x + 1/10)^2 = 11/100 (square root both sides)
x + 1/10 = (sqrt11)/10 (subtract 1/10 from both sides)
ANSWER: x = (sqrt11)/10 - 1/10, (-sqrt11)/10 - 1/10
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