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test/359907: Find a value for K so that the line through (4,K) and (-2,-1) is parallel to y=-2x+3/2.
1 solutions
Answer 256801 by robertb(4012) About Me  on 2010-10-21 20:28:29 (Show Source):
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The slope must have slope 2.(Why?) Then we must solve the equation
%28k--1%29%2F%284--2%29+=+%28k%2B1%29%2F6+=+-2.
k%2B1+=+-12,
k+=+-13.

Money_Word_Problems/359905: if a shirt cost 10.00 and the mark up rate is 60% what is the cost?

1 solutions
Answer 256799 by robertb(4012) About Me  on 2010-10-21 20:25:51 (Show Source):
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1.6C+=+10 and the cost is $6.25, after dividing 10 by 1.6.

Age_Word_Problems/359904: Bill is 8 times older than Sally the difference in their ages is 7 years; how old is Bill and how old is Sally
1 solutions
Answer 256797 by robertb(4012) About Me  on 2010-10-21 20:24:17 (Show Source):
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B+=+8S, and B-S+=+7. Then 8S+-+S+=+7 by direct substitution.
7S+=+7, and S+=+1. Bill is 8 years old.

Surface-area/359903: How do I write a formula for the perimeter P of a square in terms of its area A?
1 solutions
Answer 256796 by robertb(4012) About Me  on 2010-10-21 20:22:25 (Show Source):
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P+=+4s. Also A=+s%5E2.
Then s+=+sqrt%28A%29. Substituting into the 1st equation, then P+=+4sqrt%28A%29.

Age_Word_Problems/359900: Don is 21 years older than Betty. In 6 years Don will be twice as old as Betty. How old are they now?
1 solutions
Answer 256794 by robertb(4012) About Me  on 2010-10-21 20:17:01 (Show Source):
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D = B+21.
D+6 = 2(B+6).
By direct substitution, B+21+6= 2(B+6).
B+27 = 2B+12.
B = 15.
D = 36.

Mixture_Word_Problems/359897: melissa has$20.00 to buy tickets at the movies. each ticket costs $3.75 at the discount theater. how man tickets can she buy? how much change will she get back?
1 solutions
Answer 256793 by robertb(4012) About Me  on 2010-10-21 20:14:33 (Show Source):
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She can buy 5 tickets for a total of $18.75, and her change is $1.25.

Rational-functions/359896: what is the equation of the line parallel to y=4x+3 and with the same y-intercept as y=-3x+2
1 solutions
Answer 256791 by robertb(4012) About Me  on 2010-10-21 20:13:08 (Show Source):
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The slope of the parallel line must be 4, and its y-intercept is 2. Therefore by the slope-intercept form, the equation is y = 4x +2.

Radicals/359870: -x-5+6x=12+2x-5
solve for x please
1 solutions
Answer 256788 by robertb(4012) About Me  on 2010-10-21 20:09:43 (Show Source):
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-x-5+6x=12+2x-5
5x-5 = 2x+7
3x = 12,
x = 4.

Rectangles/359874: I have a rectangle that is three times longer than it is wide. The perimeter is 256 inched. How wide is the table. I have no further information.
1 solutions
Answer 256787 by robertb(4012) About Me  on 2010-10-21 20:08:18 (Show Source):
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L+=+3W. 2L%2B2W+=+256. Direct substitution gives 6W+%2B+2W+=+256,
8W+=+256, or W = 32 inches. The table is 32 inches wide.

Linear-equations/359893: what are the x and y intercepts for 3x-5y=-45
1 solutions
Answer 256783 by robertb(4012) About Me  on 2010-10-21 20:05:53 (Show Source):
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Express the equation in intercept form: x%2F-15%2By%2F9+=+1. (Divide both sides by -45!) Then the x-intercept is (-15,0), and the y-intercept is (0, 9).

Triangles/359880: Why must you use the largest angle to classify the triangle?
1 solutions
Answer 256782 by robertb(4012) About Me  on 2010-10-21 20:03:40 (Show Source):
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It is to be expected that a triangle will always have acute interior angles. If one of the interior angles is obtuse, then it is the only such interior angle, and the other two interior angles are acute.The triangle is then called obtuse. Same is true if one of the interior angles is a right angle (the other two angles are acute.) The triangle is then called a right triangle. If the greatest interior angle is an acute angle, then all the angles are acute, so it becomes logical to call the triangle an acute triangle.

Problems-with-consecutive-odd-even-integers/359883: The product of 2 consecutive even integers is 80. Find the integers
1 solutions
Answer 256780 by robertb(4012) About Me  on 2010-10-21 19:56:25 (Show Source):
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x%28x%2B2%29+=+80,
x%5E2+%2B+2x+=+80,
x%5E2+%2B2x+-+80+=+0,
%28x%2B10%29%28x-8%29+=+0,
Then x = -10 or x = 8.
The two pairs of numbers are -10, -8 or 8, 10.

Functions/359886: f(x) = (SQUARE ROOT OF...) 25-x^2, find the value of f(3)
1 solutions
Answer 256779 by robertb(4012) About Me  on 2010-10-21 19:53:58 (Show Source):

Linear-equations/359881: Find the equation of a line that is perpendicular to the line x=19 and contains the point (-5, 2)
1 solutions
Answer 256778 by robertb(4012) About Me  on 2010-10-21 19:52:11 (Show Source):
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The line x = 19 is a vertical line. The line perpendicular to it is then a horizontal line. Since it should pass through (-5, 2), the equation of the line is y = 2.

Numbers_Word_Problems/359877: Five times a number plus another number is 12. Their difference is 6. What are the two numbers?
1 solutions
Answer 256776 by robertb(4012) About Me  on 2010-10-21 19:46:15 (Show Source):
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5x + y = 12.
|x-y| = 6.
y = 12-5x. This implies that |x-(12-5x)| = 6.
|x-12+5x| = 6.
|6x-12| = 6,
|x-2| = 1, after dividing both sides by 6.
Then x-2 = 1 or x-2 = -1. The first equation gives x = 3, and the second, x = 1. If x = 3, y = -3. If x = 1, y = 7. The answers are then (3,-3) or (1,7).

Sequences-and-series/359876: Find the third, fourth, and fifth terms in the sequence if
A1=3, a2=6 and an= 3an-1-2an-2

1 solutions
Answer 256774 by robertb(4012) About Me  on 2010-10-21 19:41:18 (Show Source):
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a3 = a2 - a1 = 6-3 = 3,
a4 = a3 - a2 = 3-6 = -3,
a5 = a4 - a3 = -3 - 3 = -6.

Graphs/359871: Find the slope and y intercept
4x = 3y + 9
The y intercept (I believe) is (0,9)
but I am not to sure about the slope. Is it 3?
Thanks for your help
1 solutions
Answer 256772 by robertb(4012) About Me  on 2010-10-21 19:34:02 (Show Source):
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Express your equation in slope-intercept form: y+=+4x%2F3+-+3 (Transpose 9 to the left side, and then divide throughout by 3, the coefficient of x.) Therefore the slope is 4/3, and the y-intercept is (0,-3).

Systems-of-equations/359858: 2y^2 - x^2 = 1
y+1 = x

1 solutions
Answer 256770 by robertb(4012) About Me  on 2010-10-21 19:27:45 (Show Source):
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2y%5E2+-+x%5E2+=+1
y%2B1+=+x. substitute the bottom equation into the top equation:
2y%5E2+-%28y%2B1%29%5E2+=+1,
2y%5E2+-y%5E2+-+2y-1+=+1,
y%5E2+-2y-2+=+0,
y+=+%282+%2B-+sqrt%28+2%5E2-4%2A1%2A%28-2%29+%29%29%2F%282%2A1%29,
y+=+%282+%2B-+sqrt%28+12+%29%29%2F2,
y+=+%282%2B-2sqrt%283%29%29%2F2,
y+=+1%2B-sqrt%283%29. Then x+=+2%2B-sqrt%283%29.

Graphs/359485: Please help with this problem also.
Media services charges $30 for a phone and 20/month for its economy plan. Find a model that determines the total cost c(t) of operating a media service phone for t months.C(t) = $50 ??? Is that correct? Seems to easy
Use the model to find the total cost for 2 months of service
Total cost = $100 ??? Really seems to easy.
Please advise if it is correct. Thank you.

1 solutions
Answer 256518 by robertb(4012) About Me  on 2010-10-21 00:29:22 (Show Source):
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The fixed cost is the cost of the phone, $30. The variable cost is $20*t, where t is the number of months of operation. The total cost is then fixed cost plus variable cost. The total cost is then C%28t%29=20t%2B30.

Equations/359426: (x+4)^(1/2)+5x(x+4)^(3/2)=0
1 solutions
Answer 256513 by robertb(4012) About Me  on 2010-10-21 00:14:27 (Show Source):
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%28x%2B4%29%5E%281%2F2%29%2B5x%28x%2B4%29%5E%283%2F2%29=0
sqrt%28x%2B4%29%2A%281%2B5x%28x%2B4%29%29+=+0
sqrt%28x%2B4%29%2A%281%2B5x%5E2%2B20x%29+=+0,
therefore . Also x = -4.
x=%28-10%2B-sqrt%2895%29%29%2F5, and x=-4 are the final answers.

Geometry_Word_Problems/359491: one side of a rectangle is three feet more than half as long as the other side and the perimeter is 21 feet what are the dimensions of the rectangle
1 solutions
Answer 256507 by robertb(4012) About Me  on 2010-10-20 23:57:06 (Show Source):
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one side of a rectangle is three feet more than half as long as the other side and the perimeter is 21 feet what are the dimensions of the rectangle.
Let x, y be the sides of the rectangle.
y+=+%281%2F2%29x%2B3, and 2x%2B2y+=+21.
By substitution,
2x+%2B+2%2A%28%281%2F2%29x%2B3%29+=+21,
2x%2Bx%2B6+=+21,
3x+=+15,
x+=+5.

test/359508: If Matt baked cupcakes, all but 10 were unfrosted. He gave half of the frosted to his sister, half to a neighbor, and he ate half at dinner, then 6 were left. How many cupcakes did he have altogether?
1 solutions
Answer 256505 by robertb(4012) About Me  on 2010-10-20 23:52:14 (Show Source):
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If Matt baked cupcakes, all but 10 were unfrosted. He gave half of the frosted to his sister, half to a neighbor, and he ate half at dinner, then 6 were left. How many cupcakes did he have altogether?
Let x = # cupcakes in all. Then x - 10 = frosted.
%28%28%28x-10%29%2F2%29%2F2%29%2F2+=+6,
%28x-10%29%2F8+=+6,
x-10+=+48,
x+=+58.

Travel_Word_Problems/359494: Chris's average speed for a 6 hour trip was 70 mph. For the first 4 hrs, Chris drove at 62 mph. What was his average speed for his last 2 hours of his trip?
1 solutions
Answer 256504 by robertb(4012) About Me  on 2010-10-20 23:45:43 (Show Source):
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Chris's average speed for a 6 hour trip was 70 mph. For the first 4 hrs, Chris drove at 62 mph. What was his average speed for his last 2 hours of his trip?
The total distance traveled was 70+%2A+6+=+420miles. During the 1st four hours, The distance traveled was 62%2A4+=+248. Therefore 172 miles was traveled the last 2 hours, and the average speed would be 172%2F2+=+86 miles per hour.

Numeric_Fractions/359413: Six flags amusement park has found that three fifths of its customers ride the colossus roller coaster. of these, one fourth ride it again. what fraction of the customers ride the roller coaster twice?
1 solutions
Answer 256459 by robertb(4012) About Me  on 2010-10-20 20:35:22 (Show Source):
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Let c = # of customers. Then %283%2F5%29c ride the roller coaster. Of these,
%281%2F4%29%2A%283%2F5%29c ride it again. Therefore 3%2F20 of the customers ride the roller coaster again.

Miscellaneous_Word_Problems/359412: carlos is building a screen door. the height of the door is 1 foot more than twice its width. what is the width of the door if is 7 feet high?
1 solutions
Answer 256458 by robertb(4012) About Me  on 2010-10-20 20:32:05 (Show Source):
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h+=+2w+%2B+1. Now height h = 7 feet. Thus
7+=+2w+%2B+1,
6+=+2w,
w+=+3 feet.

Angles/359411: find the measure of angle a if its 30 more than 1/4 its supplement?
1 solutions
Answer 256457 by robertb(4012) About Me  on 2010-10-20 20:30:05 (Show Source):
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Let x = angle. Then
x+=+%281%2F4%29%28180-x%29++%2B30,
x+=+45+-+0.25x+%2B30,
1.25x+=+75,
x+=+60.

Inequalities/359409: -4(3-p)>5(p+1)
1 solutions
Answer 256454 by robertb(4012) About Me  on 2010-10-20 20:27:24 (Show Source):

Mixture_Word_Problems/359405: I am in college readiness, and we have a quiz tomorrow except that I do not understand liquid mitures. the problem is
how many liters of water must be added to 8 liters of a 40% acid solution to obtain a 10% acid solution?
1 solutions
Answer 256452 by robertb(4012) About Me  on 2010-10-20 20:25:30 (Show Source):
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8%2A0.40+%2B+x%2A0+=+%288%2Bx%29%2A0.10,
3.2+=+0.8+%2B+0.10x,
2.4+=+0.10x,
x+=+24 liters of water.

Expressions-with-variables/359406: 9n-2=7n+50
1 solutions
Answer 256450 by robertb(4012) About Me  on 2010-10-20 20:22:05 (Show Source):

Points-lines-and-rays/359004: Find the midpoint of the line segment PQ.
P(0,3);Q(-10,-13)
1 solutions
Answer 256182 by robertb(4012) About Me  on 2010-10-20 07:28:12 (Show Source):
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x+=+%280%2B%28-10%29%29%2F2,y+=+%283%2B%28-13%29%29%2F2, or
x+=+-5,y+=+-5. Therefore the midpoint is (-5,-5).

Travel_Word_Problems/358881: Two cars traveling toward each other are 400 miles apart. Car a is traveling 20 miles per hour faster than car b. The cars pass after 4 hours. How fast is each car traveling?
1 solutions
Answer 256181 by robertb(4012) About Me  on 2010-10-20 07:21:34 (Show Source):
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4%2A%28B+%2B+20%29%2B+4%2AB+=+400.
B+%2B+20+%2B+B+=+100, after dividing both sides by 4.
2B+=+80,
B+=+40miles per hour, the speed of B.
A+=+60miles per hour, the speed of A.