ricom39

1 Questions
19 Answers

0

1054

3

+42

old algebra

Write 10+sqrt(84) in the form (a+b)^2

ricom39 Mar 15, 2012

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Look up how many Joules are needed to warm 1 g water 1 degree.
Suppose y J
You will need totally 800 x 88 x y Joules = T Joules
1 Joule = 1 Ws
Divide T trough 2000 and you'll find the number of seconds.

As I remember this it will be about 10 minutes.

ricom39May 12, 2013

+42

0

sin ( -1) = -0,017452402

ricom39May 12, 2013

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Write your equations in the form y = rx + s
Where r is saying something on the direction of the line.
The same r, so the same direction (parallel)
r1 x r2 = -1 then perpendicular

Try now!

y = 3/8 x + 14/8 r1 = 3/8
y = -32/12 x - 15/12 => y = -8/3 x - 5/4 r2 = - 8/3
r1 * r2 = ?
3/8 * -8/3 = -1

Perpendicular!

ricom39Feb 25, 2013

+42

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2u-9=5 or 2u-9=-5
2u=14 or 2u=4
u=7 or u=2
S= {2, 7}

ricom39Dec 18, 2012

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a^2 + b^2 = c^2
(3x)^2 + (4x)^2 = 75^2

9x^2 + 16x^2 = 75^2
25x^2 = 25^2.3^2
x^2 = 5^2.3^2
x=15
So the length of the sides are 45 and 60

ricom39Nov 28, 2012

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4x^2 - 4x^2 - 12x - 9 = 8x - 28 - 1
-20x = -20
x = 1

ricom39Nov 26, 2012

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Quite simpel:

2/12 + 9/12 + 4/12 = 15/12 answer: 1/3

2/12 + 5/12 + 8/12 = 15/12 answer: 5/12

ricom39Nov 10, 2012

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There is a formule: S = 1/2 n (n + 1)

Here is n = 100

ricom39Nov 5, 2012

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4(x-2)/(x-3) + 3/x = -3/x(x-3)

4x(x-2)/x(x-3) + 3(x-3)/x(x-3) = -3/x(x-3)

x cannot be 0 or 3

4x^2 - 8x + 3x - 9 = -3

4x^2 -5x -6 = 0

(x-2)(4x+3) = 0

x = 2 or x = - 3/4

ricom39Nov 5, 2012