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# Recent problems solved by 'edjones'

edjones answered: 7568 problems
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 Polynomials-and-rational-expressions/255539: Can you please simplify the squareroot of 3x^5 times squareroot of 21x? can you please show me the process? and also how would i factor x^2-13x+36? thank-you very much 1 solutions Answer 187855 by edjones(7569)   on 2010-01-11 10:35:29 (Show Source): You can put this solution on YOUR website!sqrt(3x^5)*sqrt(21) =sqrt(3)*sqrt(x^5)*sqrt(3)*sqrt(7) =3sqrt(7x^5) . Ed
 Functions/255552: what is the domain of the function f(x)=sqrt of x^2-3x-10?1 solutions Answer 187853 by edjones(7569)   on 2010-01-11 10:17:28 (Show Source): You can put this solution on YOUR website!y=sqrt of x^2-3x-10 x^2-3x-10 cannot be negative because the sqrt of a negative number is not real. So x^2-3x-10>=0 x^2-3x-10=0 (x-5)(x+2)=0 x=5, x=-2 Now we have to test on either side of 5 and -2 to see when y is >=0 x=-5: y=25+15-10=30 x=0: y=-10 x=10 y=100-30-10=60 . Domain is X (-infinity, -2] U [5,infinity) . Ed .
 Miscellaneous_Word_Problems/255591: The sum of a certain number of positive integers is 31. What is the biggest their product can be? (1) 55296 (2) 78732 (3) 118098 (4) 49152 (5) None of the above1 solutions Answer 187850 by edjones(7569)   on 2010-01-11 09:46:40 (Show Source): You can put this solution on YOUR website!3^9*4=78732.
 Permutations/255633: computer with an old processor locks up if more than 4 application are running. 20 applications stored in program file. how many different sets of 4 can run1 solutions Answer 187845 by edjones(7569)   on 2010-01-11 09:37:25 (Show Source): You can put this solution on YOUR website!nCr=n!/((n-r)!r!) Combination of n things taken r at a time. 20C4=20!/((20-4)!4! =4845 different sets . Ed
 Trigonometry-basics/255456: find the exact value of sin 3.14 divided by 61 solutions Answer 187742 by edjones(7569)   on 2010-01-10 20:20:31 (Show Source): You can put this solution on YOUR website!314/100 * 1/6 =314/600 =157/300 . Ed
 Graphs/255195: find the domain of the function p(x)=xsquared-2x+51 solutions Answer 187596 by edjones(7569)   on 2010-01-10 12:24:01 (Show Source): You can put this solution on YOUR website!All real numbers.
 Probability-and-statistics/255295: what is the problability of getting all four problems right on a test with 4 differnet possible answers? what is the problability of getting at least one problem rgiht? for my formula i got n=4 x=4 p=1 and q=0 for the first question and then n=4 x=1 p=1 and q= 3 for the second question and the formula is n!/(n-x)!x!* p^x*q^n-x1 solutions Answer 187593 by edjones(7569)   on 2010-01-10 12:17:31 (Show Source): You can put this solution on YOUR website!what is the problability of getting all four problems right on a test with 4 differnet possible answers? what is the problability of getting at least one problem rgiht? ...IF YOU GUESS! You left this part out. Be sure to put it in next time. Expansion of (c+w)^4 gives all the probabilities. . a) Let c=probability of guessing correctly =.25 w= prob. of guessing wrongly=.75 c^4=.25^4=.0039 . b) 1-w^4 One minus prob. that all are wrong. =1-.75^4 =1-.3164 =.6836 . Ed
 Rational-functions/255236: help me solve this fraction x/12= x/13-51 solutions Answer 187511 by edjones(7569)   on 2010-01-10 01:30:11 (Show Source): You can put this solution on YOUR website!x/12= x/13 - 5 13x=12x-780 multiply each side by 156 x=-780 . Ed
 Miscellaneous_Word_Problems/255211: team A and team B build houses.If the teams work together they can build a house in 4 days. Team A working alone can complete a house in 10 days.If the team works together for 3 days, but then team B Leaves, how much longer will team A need to finish the house? yuck!1 solutions Answer 187509 by edjones(7569)   on 2010-01-10 01:21:26 (Show Source): You can put this solution on YOUR website!Yuk? Roll up your sleeves, we've got work to do! Together they do 1/4 the job in 1 day. A does 1/10 job in 1 day. . Together the do 3/4 the job in 3 days. There is 1/4 of the job left to do. How many 1/10 make 1/4? Let a=number of days left. a/10=1/4 a=10/4=5/2=2.5 days for team A to finish the job. Easy, no ifs, ands or yuks about it. . Ed
 Graphs/255183: find the domain of the function. g(x)=9/10-9x 9/10-9 is a fraction1 solutions Answer 187508 by edjones(7569)   on 2010-01-10 01:00:16 (Show Source): You can put this solution on YOUR website!g(x)=9/(10-9x) . Division by zero is not allowed. When x=what will the denominator=0? 10-9x=0 -9x=-10 x=10/9 . The domain is all real numbers except x=10/9. . Ed .
 Polygons/255152: What regular polygon has an interior angle measure to exterior angle measure ratio of 3:1? 1 solutions Answer 187506 by edjones(7569)   on 2010-01-10 00:52:47 (Show Source): You can put this solution on YOUR website!3x+x=180 4x=180 x=45 . The interior angle=45*3=135 Let n=number of sides. Int. angle=(180(n-2))/n (180(n-2))/n=135 180n-360=135n 45n=360 n=8 Octagon. . Ed
 Percentage-and-ratio-word-problems/255174: Fractions: If the cost of the science fair is \$300, how much should each school pay based on the number of students? MM 100 students WM 60 students TM 40 students1 solutions Answer 187505 by edjones(7569)   on 2010-01-10 00:28:15 (Show Source): You can put this solution on YOUR website!300/200=3/2=1.50 per student 100*1.50=\$150. 60*1.50=\$90. 40*1.50=\$60. . Ed
 Mixture_Word_Problems/255220: A swimming pool contains 15,000 gallons of water. How many gallons of chlorine must be added to bring the water to a (3/100)% solution?1 solutions Answer 187504 by edjones(7569)   on 2010-01-10 00:14:45 (Show Source): You can put this solution on YOUR website!15000*.0003=4.5 gal
 Graphs/255224: find the slope x=-3 y=11 solutions Answer 187503 by edjones(7569)   on 2010-01-10 00:10:33 (Show Source): You can put this solution on YOUR website!There is no slope, only a dot at (-3, 1).
 Rate-of-work-word-problems/254947: A swimming pool is 1 meters deep, 6 meters wide, and 30 meters long. Water is pumped into the pool at a rate of 100 liters per minute. How many hours will it take to fill the pool? (Remember that there are 1000 liters in a cubic meter).1 solutions Answer 187269 by edjones(7569)   on 2010-01-08 19:21:14 (Show Source): You can put this solution on YOUR website!6*30*1=180 cu m 180*1000=180,000 L 180000/100=1800 min 1800/60=30hrs . Ed
 Money_Word_Problems/254921: Company has a contract to sell 10,000 parts. Each part will sell for \$45.50 apiece. There is a 20% probability that expeses will be \$40,000 and an 80% probability that expenses will be \$50,000. What is the expected pretax income for the firm's sales?1 solutions Answer 187235 by edjones(7569)   on 2010-01-08 16:43:13 (Show Source): You can put this solution on YOUR website!10000*45.50=455,000 gross income .2*40000 + .8*50000=48,000 455000-48000=\$407,000. . Ed
 Probability-and-statistics/254938: John and Jane are married. The probability than John watches a certain television show is 0.4. The probability that Jane watches the show is 0.5. The probability that John watches the show, given that Jane does, is 0.7. a) find the probability that both John and Jane watch the show. b) find the probability that Jane watches the show, given that John does. c) do John and Jane watch the show independently of each other? Justify your answer. I tried the set with { WW, WD, DW, DD} with W being 'watched' and D standing for 'did not watch.' It came out that a was 1/2 x 1/2 = .25 I also tried multiplying the probabilities together and got 0.20/25 = .8 That was for a. B would be .7/5 or .7 x .5 = .35. Is that even correct? I say they could watch it independently of each other if there were other factors, but since they aren't part of the equation, I would say no. Could you sort of give me a nudge?1 solutions Answer 187234 by edjones(7569)   on 2010-01-08 16:36:50 (Show Source): You can put this solution on YOUR website!j=probability john watches m= probability jane watches . Check the Venn diagram below . . Lets take a weekly show for 10 weeks. j watches 4 shows and m watches 5 in that period. The probability that John watches the show, given that Jane does, is 0.7 This means that while m is watching one of her five shows j is also watching .7 of the time so he is watching 5*.7=3.5 shows. That leaves him only 0.5 shows to watch on his own. Now we divide the above numbers by 10 and do the Venn diagram. Put .05 in the red circle, .15 in the green circle and .35 in the intersection between the circles and .45 outside the circles for when nobody is watching the show so that the sum equals 1 . a) .35 the intersection. b) .35/.4=.875 c) Yes. .05 for j and 1.5 for m . E-mail me any more questions. This is a tough one. Let me know if it is correct or not. . Ed
 Inequalities/254931: ok the problem is 5/x is >= -1 i'm not sure how the book got the graph to long how it does i only get one section that is shaded and they have two1 solutions Answer 187221 by edjones(7569)   on 2010-01-08 15:51:42 (Show Source): You can put this solution on YOUR website!5/x >= -1 . This is a rational inequality. We have to find the zeros of the numerator and undefined parts from the denominator. 5-5=0 so -5 is the zero of the numerator when x=0 then the inequality is undefined. . Now we have to test on either side of -5 and x=0: x=-6 5/-6=-5/6 which is >-1 x=-1 5/-1=-5 which is <-1 x=1 5/1=5 which is >-1 . -5=>x>0 or (-infinity, -5] U (0.infinity) . Ed .
Circles/254908: An equilateral triangle is inscribed in a circle with a radius of 6". Find the area of the segment cut off by one side of the triangle
1 solutions

Answer 187216 by edjones(7569)   on 2010-01-08 15:14:57 (Show Source):
You can put this solution on YOUR website!
 Solved by pluggable solver: Calculate side length of equilateral triangle inscribed in the circle The circle of radius 6 with center O with an equilateral triangle ABC inscribed in it. Join edges A,B and C with center O as shown in figure. Consider Triangle AOB and AOC, 1.> .............(Sides of Equilateral triangle are equal) 2.> .............(These are radius of a circle) 3.>OA is common side to both Triangles. From conditions 1,2 and 3 Triangle AOB and AOC are congruent to each other. (SSS congruency condition) Now since triangles are congruent, Therefore, ...............(4) Similarly, ...............(5) As, Angle CAB is an angle in a equilateral triangle Hence, degrees ...............(6) Now, ..........(From (4)) degrees degrees ...........(6) Similarly, and from condition 5, degrees ...........(7) Now consider Triangle AOB, Sum of angles in a Triangle is 180 degrees. Hence, ........(From 6 and 7) ...........(8) In Triangle AOB using sine rule, Hence the side of an equilateral triangle inscribed in a circle of radius 6 is 10.3923048.

.
A(equilateral triangle)=s^2sqrt(3)/4
(10.39^2*sqrt(3))/4
=46.74 sq in
.
A(circle)=pi*r^2
=pi*6^2
=113.1 sq in
.
113.1-46.74=66.35 area of all 3 segments cut off by a side of the triangle.
66.35/3
=22.12 sq in, area of the segment cut off by one side of the triangle.
.
Ed

 Linear-equations/254877: (1) Which of the folowing functions has its vertex below the x-axis? f(x)= (x-7)^2 f(x)= x^2-8 f(x)= 2x^2 f(x)= (x+3)^2 (2) Find the minimum or maximum value of f(x)=x^2-2x-6 Then state the domain and range of the function. Answer The maximum value is 1. D: {all real numbers}; R: {y | y –7} The maximum value is 1. D: {x | x –7 }; R: {all real numbers} The minimum value is –7. D: {all real numbers}; R: {y | y –7} The minimum value is –7. D: {x | x –7 }; R: {all real numbers} (3) A toy rocket is launched from the ground level with an initial vertical velocity of 96 ft/s. After how many seconds will the rocket hit the ground? Answer 6 seconds 0 seconds or 6 seconds 0 seconds square root of 6 seconds 1 solutions Answer 187207 by edjones(7569)   on 2010-01-08 14:31:57 (Show Source): You can put this solution on YOUR website!2) f(x)=a^2+bx+c x^2-2x-6 a is positive so there is a minimum. minimum at x=-b/2a=2/2=1 minimum at y=1-2-6=-7 Domain is all real numbers Range is [-7, infinity) . Ed .
 Polynomials-and-rational-expressions/254844: (1-r)(1-r)1 solutions Answer 187198 by edjones(7569)   on 2010-01-08 14:08:51 (Show Source): You can put this solution on YOUR website!r^2-2r+1 FOIL
 Triangles/254902: A triangle has two sides of length 7 and 9. What value could the length of the third side be1 solutions Answer 187194 by edjones(7569)   on 2010-01-08 14:01:28 (Show Source): You can put this solution on YOUR website!Let x be the length of the 3rd side. my final answer . Ed
 Equations/254900: F(x)= x^3-5x^2+144x-720 I got one of the zeroes (x=5) I need the other 2... they should be imaginary numbers.1 solutions Answer 187192 by edjones(7569)   on 2010-01-08 13:57:47 (Show Source): You can put this solution on YOUR website!x=5 x-5=0 (x^3-5x^2+144x-720)/(x-5) Long division =x^2+144 x^2+144=0 x^2=-144 x=+-sqrt(-144) =+-12i the other 2 zeros . Ed
 Inequalities/254893: I'm a little lost on how to solve this problem. Solve the rational inequality 3x-1/x-8 ≤ 01 solutions Answer 187189 by edjones(7569)   on 2010-01-08 13:47:22 (Show Source): You can put this solution on YOUR website!3x-1/x-8 ≤ 0 This is a rational inequality. We have to find the zeros of the numerator and undefined parts from the denominator. 3x-1=0 3x=1 x=1/3 . when x=8 then x-8 = 0 and the inequality is undefined. Now we test points larger and smaller than 1/3 and 8 to see if the fraction is <= 0 x=0: -1/-8=1/8 is >0 x=1: 3-1/1-8=2/-7=-2/7 is <0 x=10 30-1/10-8=29/2 is >0 . 1/3<=x<8 or x[1/3, 8) . Ed .
 Equations/254726: a line passes through (3a,4) and (-1,2) and is parallel to -4x +2y= 6 find a1 solutions Answer 187091 by edjones(7569)   on 2010-01-08 02:41:24 (Show Source): You can put this solution on YOUR website!(3a,4) and (-1,2) -4x +2y= 6 . 2y=4x+6 y=2x+3 the slope, m=2. . (4-2)/(3a-(-1))=2 2/(3a+1)=2 2/1=2 so 3a+1=1 and a=0 . Ed
 Polynomials-and-rational-expressions/254750: a rectangular painting with a width of x centimeters has an area of x^2+50x square centimeters. Find a binomial that represents the lenght.1 solutions Answer 187090 by edjones(7569)   on 2010-01-08 02:26:28 (Show Source): You can put this solution on YOUR website!Let y=length L*W=A xy=x^2+50x y=x+50 . Ed
 Square-cubic-other-roots/254753: (sqrt3 - sqrt 5)^2 ???1 solutions Answer 187089 by edjones(7569)   on 2010-01-08 02:22:04 (Show Source): You can put this solution on YOUR website!(sqrt(3)-sqrt(5))^2 Let a=sqrt(3) and b=sqrt(5) (a-b)^2 a^2-2ab+b^2 3-2sqrt(15)+5 8-2sqrt(15) . Ed
 logarithm/254759: What does x= ? 2log base5(4x+1)=71 solutions Answer 187088 by edjones(7569)   on 2010-01-08 02:09:24 (Show Source): You can put this solution on YOUR website!2log[5](4x+1)=7 log[5](4x+1)=7/2 5^(log[5](4x+1))=5^(7/2) 4x+1=125sqrt(5) 4x=125sqrt(5)-1 x=(125sqrt(5)-1)/4 . Ed
 Probability-and-statistics/254698: Of a class of 25 students, 18 have brown eyes. If 2 students are chosen at random, what is the probability that both students have brown eyes.1 solutions Answer 187028 by edjones(7569)   on 2010-01-07 19:52:39 (Show Source): You can put this solution on YOUR website!nCr=n!/((n-r)!r!) Combination of things r at a time. . 18C2/25C2 =153/300 =.51 . Ed
 expressions/254406: Expand binomial. (7-2x)^6 I know I can either use the Pascal's Triangle or the binomial theorem.1 solutions Answer 186731 by edjones(7569)   on 2010-01-07 01:27:35 (Show Source): You can put this solution on YOUR website!Wrong. Multiply 7-2x times itself. then multiply 7-2x times the result and again etc. . Ed
 Problems-with-consecutive-odd-even-integers/254091: Find two consecutive whole numbers such that 3/4 of the first number is 5 more than 1/2 the second number. Thank you.1 solutions Answer 186495 by edjones(7569)   on 2010-01-06 12:01:04 (Show Source): You can put this solution on YOUR website!Let the numbers be x and x+1 .75x=.5(x+1)+5 .75x=.5x+.5+5 .75x=.5x+5.5 .25x=5.5 x=22 x+1=23 . Ed