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Recent problems solved by 'timmy1729'

timmy1729 answered: 23 problems
Geometry_proofs/100972: this a worksheet i do NOT understand. but if i know how to do at least one problem, i should be able to get them all. the directions are "Complete the argument, giving a reason for each step"
10. Given: (segment) JK is congruent to (segment) SH and (segment) SH is congruent to (segment) MN
Prove: (segment) JK is congruent to (segment) MN.
statement | reason
JK is congruent to SH ?
SH is congruent to MN ?
JK is congruent to MN segment addition postulate
i thought that the first two were given, but on the other ones it has given typed in, i found out the 3rd reason because our teacher gave us that one in class. I really don't know what to do, except we answer with a proof, properties, and/or postulates, and I appreciate your help.
1 solutions

Answer 73519 by timmy1729(23) About Me  on 2007-09-28 07:40:56 (Show Source):
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If I understand your question correctly, this is just the associative property.
If a=b and b=c then a=c.


Points-lines-and-rays/99178: You are to estimate the measure of the angle created by the hour and minute hands on the clocks and classify the angle as being acute, straight, right or obtuse:
5:00 Estimate:
Angle:
1 solutions

Answer 73217 by timmy1729(23) About Me  on 2007-09-26 14:26:26 (Show Source):
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Well, if you look at 3:00, that is a right angle. Also, the face of a clock is a circle. That is 360 degrees. There are twelve numbers on the clock face so that says that every number of the clock face is 30 degrees. So, you estimate and answer for 5:00 should both easily be 150 degrees since 5 * 30 = 150. It is obtuse because it is larger than 90 degrees. Acute would be less than 90.


Square-cubic-other-roots/100511: How do we square trinomials?
1 solutions

Answer 73216 by timmy1729(23) About Me  on 2007-09-26 14:13:27 (Show Source):
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You have to use the distributive property for every term on the whole trinomial. It's messy, but you have to do it.
For example: %28x+%2B+y+%2B+z%29%5E2

In reality, this is what you are doing when you square a binomial. This works for any polynomial.


Linear-equations/100562: I need help finding the slope of the line passing through (-2,4) and (-2,-5).
can anyone help me please? I seem to find myself with no solution for this one.
I have -5-4/-2 +2 = -9/0 Could that be right?????????????
1 solutions

Answer 73214 by timmy1729(23) About Me  on 2007-09-26 13:49:26 (Show Source):
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When your x terms are equal, the slope is simply zero. That line segment is just a straight line on x=-2 between 4 and -5.


Complex_Numbers/100060: given the following two complex numbers, a=3+7i and b=-2-2i,calculate the following
a+b
a-b
a*b
a/b
1 solutions

Answer 72864 by timmy1729(23) About Me  on 2007-09-24 13:30:33 (Show Source):
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given the following two complex numbers, a=3+7i and b=-2-2i,calculate the following
a+b
a-b
a*b
a/b
Ok, for the most part, treat i like a variable. a+%2B+b+=+3+%2B+7i+-2+-+2i
3+%2B+7i+-2+-+2i+=+1%2B5i
a+-+b+=+3+%2B+7i+-%28-2+-+2i%29+=+3+%2B+7i+%2B+2+%2B+2i+=+5+%2B+9i
a*b is just simply: %283%2B7i%29%28-2-2i%29+=+-6+-+6i+-+14i+-+14i%5E2
Remember that i^2 = -1. So we simplify into: -6+-+20i+%2B+14+=+8+-+20i
a/b is %283%2B7i%29%2F%28-2-2i%29
To simplify, you multiply the numerator and denominator by the denominator's complex conjugate which is -2+2i.
%28%283%2B7i%29%28-2%2B2i%29%29%2F%28%28-2-2i%29%28-2%2B2i%29%29
%28-6%2B6i-14i-14%29%2F%284+-4i+%2B+4i+%2B4%29
%28-20-8i%29%2F%288%29
%284%28-5-2i%29%29%2F%288%29
%28-5-2i%29%2F2


Triangles/98932: Can somebody please help me solve this question: In a right triangle, the length of the hypotenuse is 5 and the length of one of the legs is 3, determine the tangents of all three angles. Could you also please show your work, I would really appreciate it.
Thank you very much
1 solutions

Answer 72858 by timmy1729(23) About Me  on 2007-09-24 12:30:33 (Show Source):
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This is where learning Pythagorean Triples is helpful. The smallest one is the 3,4,5 right triangle. So, the measure of the other leg is 4. Fortunately, you are in luck. Since Tangent is sine/cosine(or opposite/adjacent), you only have to find two tangents. The tangent for the right angle is undefined. It would be 1/0 and we know that you can't do that. If you picture it on the unit circle, sine is the y axis and cosine is the x axis. As you move up the circle towards 90 degrees, your sine(y) approaches 1. However, your cosine(x) approaches zero. The other tangents however are easy. Just remember SOH CAH TOA. Sine is opposite/hypotenuse, cosine is adjacent/hypotenuse, and tangent is opposite/adjacent. So your other two tangents are 3/4 and 4/3.


Numbers_Word_Problems/99588: Number Problem. Find two consecutive positive integers such that the sum of their square is 85
1 solutions

Answer 72454 by timmy1729(23) About Me  on 2007-09-21 15:18:22 (Show Source):
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x%5E2+%2B+%28x%2B1%29%5E2+=+85
Make x one of those numbers and the x+1 would be the next consecutive number.
x%5E2+%2B+x%5E2+%2B+2x+%2B+1+=+85
2x%5E2+%2B+2x+%2B+1+=+85
2%28x%5E2+%2B+x%29+=+84
x%5E2+%2B+x+=+42 then x%5E2+%2B+x+-+42+=+0
%28x+%2B+6%29%28x+-+7%29+=+0 so x+=+-6 and x+=+7 are solutions. Since a negative squared is positive, you can just use 6 and 7.
6%5E2+%2B+7%5E2+=+85
36+%2B+49+=+85


Numbers_Word_Problems/99590: solve each equation for x
2(x-5)^2=3
1 solutions

Answer 72451 by timmy1729(23) About Me  on 2007-09-21 14:59:04 (Show Source):
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2%28x-5%29%5E2=3
I would personally expand the %28x-5%29%5E2 first.
That gives us:
2%28x%5E2+-+10x+%2B+25%29+=+3
Then multiply by the 2:
2x%5E2+-+20x+%2B+50+=+3
Then subtract the 3:
2x%5E2+-+20x+%2B+47+=+0
You aren't going to like this, but you have to use the quadratic formula for this one.
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 2x%5E2%2B-20x%2B47+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-20%29%5E2-4%2A2%2A47=24.

Discriminant d=24 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--20%2B-sqrt%28+24+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-20%29%2Bsqrt%28+24+%29%29%2F2%5C2+=+6.22474487139159
x%5B2%5D+=+%28-%28-20%29-sqrt%28+24+%29%29%2F2%5C2+=+3.77525512860841

Quadratic expression 2x%5E2%2B-20x%2B47 can be factored:
2x%5E2%2B-20x%2B47+=+2%28x-6.22474487139159%29%2A%28x-3.77525512860841%29
Again, the answer is: 6.22474487139159, 3.77525512860841. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B-20%2Ax%2B47+%29


Systems-of-equations/98109: 5x/7-2x/5=6/35 These are fractions 5x, 2x, 6 are all the numerator...
1 solutions

Answer 72448 by timmy1729(23) About Me  on 2007-09-21 14:47:34 (Show Source):
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%285x%29%2F7-%282x%29%2F5+=+6%2F35 To solve this, multiply by 5%2F5 in the first fraction and 7%2F7 in the second. That makes:
%2825x%29%2F35-%2814x%29%2F35+=+6%2F35
Now multiply both sides by 35 to get rid of the fractions.
25x+-+14x+=+6
That gives us 11x+=+6 and x+=+6%2F11


test/99554: Determine whether the square root of 77 is rational or irrational. Answer: A) Irrational B) Rational
I say irrational since there is no square.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Determine if (a square root symbol with a - inside it) is rational or irrational. Answer: A) Irrational B) Rational
I say: A) Irrational There is a negative symbol, also there is no number.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Find the altitude of the triangle.
the sides (height) are each 13 and the base (bottom) is 10.
Answer: ????
This one I can not find a formula in my books for solving this.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Evaluate (the square root symbol with 9 over 16 inside it) if possible.
I say not possible since it is not a whole number with a solution.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Evaluate (small 3 next to the square root symbol with 1 over 64 inside it) if possible.
I say not possible since it is not a whole number with a solution.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Am I on the right track? This is a large assignment and due tonight. These are the only ones I am doubting myself on and need your help. Thanks! ;-)

1 solutions

Answer 72446 by timmy1729(23) About Me  on 2007-09-21 14:21:53 (Show Source):
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sqrt%2877%29 is irrational. For a number to be rational, it must be able to be expressed as a fraction of two integers a%2Fb in lowest terms(prime numbers).
One major thing to know, and you should investigate this for yourself, is that there is no prime number that will have a rational square root. 77 is a product of 11 and 7, both are primes and that means that it will not have a rational square root.
__________
Is sqrt%28-x%29 rational or irrational? Well, that all depends on the x. It will definitely have a complex root(imaginary), but that doesn't mean that it will be irrational. It all depends on the x for the same reason in the first question.
___________
Is that a right triangle? And what do you mean by altitude in regards to the triangle?
____________
The rule is sqrt%28a%2Fb%29+=+sqrt%28a%29%2Fsqrt%28b%29 so your answer is sqrt%289%29%2Fsqrt%2816%29+=+3%2F4. This also applies to your next question.
The cube root of 1/64. Same thing as above except for cube roots. The cube root of 1 = 1; the cube root of 64 = 4. So the cube root of 1/64 = 1/4.


Distributive-associative-commutative-properties/99550: Use distributive property to rewrite each expression.
9xy-21xyz
1 solutions

Answer 72408 by timmy1729(23) About Me  on 2007-09-21 09:26:02 (Show Source):
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You need to find the greatest common divisor. In this case it is 3xy. So it would be 3xy%2A%283-7%2Az%29


Numeric_Fractions/99520: Please help me. I am having problem with this question.
Anne is pulling on a 60-foot rope attached to the top of a 48-foot tree while Walter is cutting the tree at its base. How far from the base of the tree is Anne standing?
Thank you
1 solutions

Answer 72406 by timmy1729(23) About Me  on 2007-09-21 08:33:58 (Show Source):
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Ahh. This is a simple application of the Pythagorean Theorem! Think of the rope that Anne is pulling on as the hypotenuse since she is standing away from the tree and the rope is attached to the top of the tree and the problem said that the rope is longer than the tree's height. Then, think of the height of the tree as a side of a right triangle.
__|\
__|_\
48|__\_60
__|___\
__|____\
____x
Let's call x the distance that Anne is from the tree. The theorem is
a%5E2+%2B+b%5E2+=+c%5E2 so in our case a+=+48 and c+=+60.
So a%5E2+=+2304 & c%5E2+=+3600.
Then 2304+%2B+x%5E2+=+3600
x%5E2+=+3600+-+2304 so x%5E2+=+1296
Then x+=+36 so Anne is standing 36ft from the tree.
Also, if you notice, 48 and 60 are multiples of 12. If you divide them by 12 you get 4 and 5. That follows special triangles with sides called Pythagorean Triples. One of them is 3,4,5. So if you can notice a right triangle as having two of those sides, you can immediately know what the third side is. But, remember always show your work to get full credit in class ;-)


Square-cubic-other-roots/98008: I need help factoring this:
x^2-2xy+y^2-a^2-2ab-b^2
Thanks for your help and time.
1 solutions

Answer 72319 by timmy1729(23) About Me  on 2007-09-20 15:29:53 (Show Source):
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Divide and conquer! Split this up and you will get it.
x%5E2-2%2Ax%2Ay%2By%5E2 is the first part. This is a simple expansion of
%28x-y%29%5E2
The second part: a%5E2-2%2Aa%2Ab-b%5E2 is a simple expansion of
%28a%2Bb%29%5E2 if you first factor out a -1, which is already in the problem.
-1%2A%28a%5E2%2B2%2Aa%2Ab%2Bb%5E2%29 This is done when you put your parentheses around the second polynomial a%5E2-2%2Aa%2Ab-b%5E2
So, the factored version is
%28x-y%29%5E2-%28a%2Bb%29%5E2


Word_Problems_With_Coins/99394: This question is from textbook beginning and intermediate algebra
A coin collector has 1.70 in dimes and nickels. She has two more dimes than nickels. How many nickels does she have
1 solutions

Answer 72315 by timmy1729(23) About Me  on 2007-09-20 15:17:41 (Show Source):
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Let x be the number of nickels. So .05x is the amount of money in nickels and 0.10(x+2) is the amount of money in dimes since there are two more dimes than nickels. Think "number of nickels + 2 = number of dimes. So, .10(x+2) + 0.05x = $1.70.
To make this a lot easier, let's multiply it all by 100 to get rid of the decimal, which we will replace later.
10(x+2) + 5x = 170 That's much better isn't it?
10x + 20 + 5x = 170 Use the distributive property.
15x + 20 = 170 Add your x's
15x = 150 Subtract the 20 from both sides, now divide
x = 10 So there are 10 nickels.
Now, back to the original form:
0.10(10 + 2) + 0.05(10) = 1.70
0.10(12) + 0.05(10) = 1.70
1.20 + .50 = 1.70.


Rational-functions/93783: This question is from textbook
Observe the following pattern and state a generalization based on the pattern:
1 + 3=2(2)
1 + 3 +5=3(2)
1 + 3 + 5 + 7=4(2)

1 solutions

Answer 72312 by timmy1729(23) About Me  on 2007-09-20 15:00:52 (Show Source):
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You are starting with 1 and adding 2 to it each line. The x in x(y) is the number of times you add y to 1.


Exponents/99380: Hello, can you please help me solve this problem? I've asked mathnerds and read purple math and no one can help me solve it. I entered the problem here but it was returned stating No functions. The question is:
If x does not equal 0, then (2^4x)(8^2x) =
Thanks for your help, Susan
1 solutions

Answer 72311 by timmy1729(23) About Me  on 2007-09-20 14:48:43 (Show Source):
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If x does not equal 0, then (2^4x)(8^2x) =
(2^4x)(2^3)^2x =
(2^4x)(2^6x) =
2^(4x+6x) =
2^(10x) =
(2^10)^x = 1024^x


Functions/98006: 22/21 = 127/x
what is the value of x?
I have 121.27272727...
but I dont think that is right.
1 solutions

Answer 72308 by timmy1729(23) About Me  on 2007-09-20 14:17:41 (Show Source):
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Your answer is correct.
22/21 = 127/x
22x = 21*127
x+=+%2821%2A127%29%2F22+=+121.272727272727


percentage/97998: A large bottle of juice contains 64 oz. A carton holds 12 bottles. How many gallons are there in 20 cartons?
1 solutions

Answer 72307 by timmy1729(23) About Me  on 2007-09-20 14:08:54 (Show Source):
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20+%2A+12+=+240 bottles.
240+%2A+64+=+15360 oz of juice.
There are 128 ounces to a gallon, so divide 15360 by 128 and you have the number of gallons.
15360%2F128+=+120 gallons.


Distributive-associative-commutative-properties/99296: use the distibutive property to simplify
8*5-12*5
1 solutions

Answer 72303 by timmy1729(23) About Me  on 2007-09-20 12:44:07 (Show Source):


Polynomials-and-rational-expressions/99338: Evaluate the following
sqrt (4 / 25 )
1 solutions

Answer 72293 by timmy1729(23) About Me  on 2007-09-20 11:53:13 (Show Source):
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sqrt%284%2F25%29
You need to know if 4 and 25 are perfect squares or not. If they are not, then you have to do some algebra. Otherwise, you can just take their square roots.
sqrt%284%2F25%29+=+2%2F5
Then check %282%2F5%29%5E2+=+4%2F25


Quadratic_Equations/99342: Solve: x2(squared)+2x-35=0
1 solutions

Answer 72291 by timmy1729(23) About Me  on 2007-09-20 11:37:00 (Show Source):
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B2x%2B-35+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%282%29%5E2-4%2A1%2A-35=144.

Discriminant d=144 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-2%2B-sqrt%28+144+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%282%29%2Bsqrt%28+144+%29%29%2F2%5C1+=+5
x%5B2%5D+=+%28-%282%29-sqrt%28+144+%29%29%2F2%5C1+=+-7

Quadratic expression 1x%5E2%2B2x%2B-35 can be factored:
1x%5E2%2B2x%2B-35+=+1%28x-5%29%2A%28x--7%29
Again, the answer is: 5, -7. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B2%2Ax%2B-35+%29


Pythagorean-theorem/99366: This question is from textbook
Ok
We have a right triangle, the hypotanuse is R+4, one of the legs is R and one is 8. I get (4+r)^2=r^2+8^2 .. how do i solve this with out the r^2 canceling out?
1 solutions

Answer 72285 by timmy1729(23) About Me  on 2007-09-20 10:42:27 (Show Source):
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%28r+%2B+4%29%5E2+=+r%5E2+%2B+8%5E2 is the correct setup.
When you do the algebra on this, I wouldn't worry about the r%5E2 canceling out.
Here is how I would work this.
%28r+%2B+4%29%5E2+=+r%5E2+%2B+64
r%5E2+%2B+8r+%2B+16+=+r%5E2+%2B+64 Then clean this up a bit. Cancel the r%5E2 and subtract the 16 on both sides.
8r+=+48 Then divide both sides by 8 and you're done.
r+=+6
So, the sides for the triangle are 6, 8, and 10. If you cut each in half, this is a special type of right triangle called a 3,4,5 triangle.


Polynomials-and-rational-expressions/99345: I have a question about this problem.
Subtract and express in simplest form:
5x-3/6 - x + 3/6
is the answer 4x - 1?
1 solutions

Answer 72280 by timmy1729(23) About Me  on 2007-09-20 10:10:29 (Show Source):
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If you rearrange this, you can work this easily.
5x+-+x+-+3%2F6+%2B+3%2F6.
The fractions add up to zero so they go away. You are left with 5x-x, which would be
5x+-+x+=+4x.