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Recent problems solved by 'edjones'

edjones answered: 7568 problems
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Square-cubic-other-roots/241792: u-3(square root of u)-10=0 Hint: let x= square root of u, so x squared = u 1 solutions Answer 177087 by edjones(7569)   on 2009-11-22 19:07:30 (Show Source): You can put this solution on YOUR website! u-3sqrt(u)-10=0 u-10=3sqrt(u) u^2-20u+100=9u square each side. u^2-29u+100=0 (u-25)(u-4)=0 u=25, u=4 u=25 is the only answer. If you check u=4 you will find that it is extraneous. . Ed

Coordinate-system/241791: please help me in graphing parabolas y=x^2 - 2 1 solutions Answer 177082 by edjones(7569)   on 2009-11-22 18:53:13 (Show Source): You can put this solution on YOUR website! To graph it you don't have to figure out the problem. Create a table with x and y at the top. put in a value for x and calculate the value for y. put a dot on graph paper for those values. Use small whole numbers for x values and don't forget negative values for x and x=zero. pretty soon you'll have a parabola. . Ed

Numbers_Word_Problems/241464: how many integers greater than 10 and less than one hundred are increased by nine when their digits are reversed 1 solutions Answer 176935 by edjones(7569)   on 2009-11-22 09:22:00 (Show Source): You can put this solution on YOUR website! 8 12, 23, 34, 45, 56, 67, 78, 89. . Ed

percentage/241528: What is 33 1/3 of 3500 1 solutions Answer 176927 by edjones(7569)   on 2009-11-22 08:44:26 (Show Source): You can put this solution on YOUR website! 100/3 * 3500 = 350000/3

Linear-equations/241534: can someone please tell me the method to solving this linear equation? 3n-1/5 + n/2 = 2 / means over as in 5 over 10 (5 divided by 10) 1 solutions Answer 176925 by edjones(7569)   on 2009-11-22 08:41:13 (Show Source): You can put this solution on YOUR website! 3n-1/5 + n/2 = 2 30n-2+5n=20 multiply each side by 10 (LCM) to eliminate fractions. 35n=22 n=22/35 . Ed

Quadratic_Equations/241543: Here's my question. Graph each parabola. Identify the vertex, intercepts, and the maximum or minimum y-value. f(x) = 16 – x^2 Once I figure out the problem then I should be able to graph it I hope. Thanks. 1 solutions Answer 176922 by edjones(7569)   on 2009-11-22 08:36:10 (Show Source): You can put this solution on YOUR website! To graph it you don't have to figure out the problem. Replace f(x) with y. Create a table with x and y at the top. put in a value for x and calculate the value for y. put a dot on graph paper for those values. Use small whole numbers for x values and don't forget negative values for x and x=zero. pretty soon you'll have a parabola. . Ed

Equations/241548: How do I Factor Completely factory 4x^4-16x^3+32x^2 1 solutions Answer 176918 by edjones(7569)   on 2009-11-22 08:24:34 (Show Source): You can put this solution on YOUR website! 4x^4-16x^3+32x^2 4x^2(x^2-4x+8) . Ed

Equations/241549: I need help with this problem Multiply (-3x)^2 (4x^6)^2= 1 solutions Answer 176917 by edjones(7569)   on 2009-11-22 08:22:51 (Show Source): You can put this solution on YOUR website! (-3x)^2 (4x^6)^2 =9x^2 * 16x^12 powers of powers are multiplied. =144x^14 powers * powers are added. . Ed

Geometry_Word_Problems/241555: The ratio of the area of two circle is 16/9. What is the ratio of their circumference? a. 4/3 b. 16/9 c. 32/18 d. 256/81 1 solutions Answer 176916 by edjones(7569)   on 2009-11-22 08:17:07 (Show Source): You can put this solution on YOUR website! pi*r^2/pi*r^2=16/9 pi cancels out. area/area r/r=4/3 sqrt of each side 2pi*r/2p*r=4/3 [2pi cancels out] circumf/circumf . Ed

Linear_Equations_And_Systems_Word_Problems/241564: The base of an iscosceles triangle is 4/3cm. The perimeter of the triangle is 4 2/15cm. What is the length of either of the remaining sides? 1 solutions Answer 176913 by edjones(7569)   on 2009-11-22 08:05:35 (Show Source): You can put this solution on YOUR website! 4/3=20/15, 4 2/15=62/15 62/15 - 20/15 = 42/15 42/15 * 1/2 = 21/15 = 7/5 cm . Ed

Rational-functions/241530: 1019 is what percentage of 3500 1 solutions Answer 176902 by edjones(7569)   on 2009-11-22 00:50:35 (Show Source): You can put this solution on YOUR website! 1019/3500 =.2911...=29.11% . Ed

logarithm/241460: 3^(x^2+1)=243 solve for x. please explain 1 solutions Answer 176849 by edjones(7569)   on 2009-11-21 19:10:17 (Show Source): You can put this solution on YOUR website! 3^(x^2+1)=243 3^(x^2+1)=3^5 log[3](3^(x^2+1)=log[3](3^5) x^2+1=5 x^2=4 x=2, x=-2 . Ed

Radicals/241468: Simplify: (square root of 3y^2)^6 1 solutions Answer 176837 by edjones(7569)   on 2009-11-21 18:45:01 (Show Source): You can put this solution on YOUR website! sqrt(3y^2)^6 (3^(1/2)y)^6 3^3y^6 27y^6 . Ed

logarithm/241397: how to solve: 4^(3x-1)=3^(x-1) i can't rember how to solve for x. i am lost. 1 solutions Answer 176789 by edjones(7569)   on 2009-11-21 15:42:56 (Show Source): You can put this solution on YOUR website! 4^(3x-1)=3^(x-1) log[4](4^3x-1)=log[3](3^(x-1))/log[3](4) Change of base formula from 3 to 4 on the right side. 3x-1=(x-1)/1.2619 3.7856x-1.2619=x-1 2.7856x=.2619 x=.094... . Ed

Probability-and-statistics/241382: Suppose that the probability that a new medication will cause a bad side effect is 0.03. If this medication is given to 150 people, what is the probability that more than three of them will experience a bad side effect? Round answer to 4 decimal places. I think I know how to compute for "exactly three students," but I cannot figure out how to do "more than three students" Here's how I approached "exactly three": p = 0.03, q = 1 - p = 0.97, n = 150 P(r, n) = nCr (p)^r * (q)^(n - r) P(3, 150) = 150C3 * 0.03^3 * 0.97^147 = 0.1691 Since I am trying to figure out how to do these types of problems on my own, please include the steps. Thank you! 1 solutions Answer 176783 by edjones(7569)   on 2009-11-21 15:00:49 (Show Source): You can put this solution on YOUR website! You are correct so far as you have gone. Now do the same procedure for exactly 2, 1 and 0 students. Find the sum of the 4 probabilities and subtract it from 1 and you have your answer. . Ed

Inequalities/241389: How do I solve: 7y-12 is less than 8y+5 1 solutions Answer 176782 by edjones(7569)   on 2009-11-21 14:47:11 (Show Source): You can put this solution on YOUR website! 7y-12 < 8y+5 add -7y-5 to each side. y>-17 . Ed

Linear-equations/241386: x + y =5 2x - y =4 -2x +-2y = -10 2x-y =4 2x - y = 4 2x -2 =4 3y -6 __ ___ 3 = 3 y = -2 __ then lost - is this right so far and can you show me how to do problem? 1 solutions Answer 176781 by edjones(7569)   on 2009-11-21 14:39:28 (Show Source): You can put this solution on YOUR website! x + y =5 2x - y =4 . x=5-y 2(5-y)-y=4 Replace x with 5-y. 10-2y-y=4 -3y=-6 y=2 x=3 . Ed

Mixture_Word_Problems/241234: Could someone please help me with this mixture problem? I have been pouring over it for two days (total of over 4 hours), and have tried various methods none of them yielding the correct answer. A mechanic has 363 gallons of gasoline and 17 gallons of oil to make gas/oil mixtures. He wants one mixture to be 6% oil and the other mixture to be 2.5% oil. If he wants to use all of the gas and oil, how many gallons of gas and oil are in each of the resulting mixtures? 1 solutions Answer 176699 by edjones(7569)   on 2009-11-21 00:36:58 (Show Source): You can put this solution on YOUR website! Let x=gals of gas required to make a .025 mixture. Let y=gals of oil required to make a .025 mixture. . A) y/(x+y)=.025 B) (17-y)/(363-x+17-y)=.06 . A) y=.025x+.025y .975y=.025x y=.0256x . B) (17-.0256x)/(380-x-.0256x)=.06 17-.0256x=22.8-.0615x .0359x=5.8 x=161.56 gal . A) y/(161.56+y)=.025 y=4.039+.025y .975y=4.039 y=4.142 gal It wont be exact because of rounding errors. . Ed

Permutations/241104: an octagon has 8 sides. How many diagnals does an octagon have?? my answer is 28 diagnals. 1 solutions Answer 176612 by edjones(7569)   on 2009-11-20 16:04:59 (Show Source): You can put this solution on YOUR website! 20 There are 5 diagonals for each point. 8*5=40. Half are repetitions. 40/2=20 . Ed

Square-cubic-other-roots/241151: the square root of 49 is how much less than four squared? 1 solutions Answer 176609 by edjones(7569)   on 2009-11-20 16:00:27 (Show Source): You can put this solution on YOUR website! sqrt(49)=7 4^2=16 16-7=9 . Ed

Miscellaneous_Word_Problems/241163: 4 more than 3 how would i right that 4+3? 1 solutions Answer 176608 by edjones(7569)   on 2009-11-20 15:58:14 (Show Source): You can put this solution on YOUR website! 3+4

Geometry_Word_Problems/241053: The ratio of the diameters of two circles is 1:4. The ratio of their radii is A) 1:2 B) 1:4 C) 1:8 D) 1:16 1 solutions Answer 176536 by edjones(7569)   on 2009-11-20 04:24:58 (Show Source): You can put this solution on YOUR website! B

Systems-of-equations/240941: solve y=x+3 y=2x+4 1 solutions Answer 176502 by edjones(7569)   on 2009-11-19 20:03:05 (Show Source): You can put this solution on YOUR website! y=x+3 y=2x+4 2x+4=x+3 x=-1 y=2 . Ed

Quadratic_Equations/240939: Polynomials (y^3)^2 Please help me Thank you 1 solutions Answer 176499 by edjones(7569)   on 2009-11-19 19:58:19 (Show Source): You can put this solution on YOUR website! (y^3)^2 =y^6 because 3*2=6 . Ed

Number-Line/240943: what are the 2 numbers that are equal distance from zero 1 solutions Answer 176498 by edjones(7569)   on 2009-11-19 19:54:09 (Show Source): You can put this solution on YOUR website! 2 and -2

Radicals/240945: simplify the square root of 56 divided by the square root of 3 1 solutions Answer 176494 by edjones(7569)   on 2009-11-19 19:51:20 (Show Source): You can put this solution on YOUR website! sqrt(56)/sqrt(3) =sqrt(4*14)/sqrt(3) =2sqrt(14)/sqrt(3) * sqrt(3)/sqrt(3) =2sqrt(42)/3 . Ed

Quadratic_Equations/240936: How do you solve the following quadratic equations: -6(u+5)^2=120 3s^2-1=7s^2 1 solutions Answer 176489 by edjones(7569)   on 2009-11-19 19:34:21 (Show Source): You can put this solution on YOUR website! -6(u+5)^2=120 (u+5)^2=-20 u^2+10u+25=-20 u^2+10u+45=0 u^2+10u =-45 u^2+10u+25=-45+25 Completing the square (u+5)^2=-20 u+5=+-sqrt(-20) Take sqrt of each side. u=-5+-2sqrt(-5) u=-5+2sqrt(5)i, u=-5-2sqrt(5)i . Ed

expressions/240905: (M + 11) + (N + 44) 1 solutions Answer 176482 by edjones(7569)   on 2009-11-19 19:20:43 (Show Source): You can put this solution on YOUR website! m+11+n+44 =m+n+55 . Ed

Polynomials-and-rational-expressions/240914: Factor. x^2 –3xy -18y^2 1 solutions Answer 176479 by edjones(7569)   on 2009-11-19 19:18:20 (Show Source): You can put this solution on YOUR website! x^2 –3xy -18y^2 =(x-6)(x+3) . Ed

Miscellaneous_Word_Problems/240918: Give an example of the sum of two binomials that is a trinomial. 1 solutions Answer 176476 by edjones(7569)   on 2009-11-19 19:17:10 (Show Source): You can put this solution on YOUR website! (a+b)+(b+c)=a+2b+c

Linear-systems/240926: i need help on solving for elmination, i get confused. Problem: 2x+6y=17 2x-10y=9 break it down for me step by step, if you can..thank you! :) 1 solutions Answer 176474 by edjones(7569)   on 2009-11-19 19:13:53 (Show Source): You can put this solution on YOUR website! 2x+6y=17 2x-10y=9 ----------------subtract ==>16y=8 y=1/2 . 2x+3=17 replace y with 1/2 2x=14 x=7 . Ed