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# Recent problems solved by 'scott8148'

scott8148 answered: 6619 problems
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 Expressions-with-variables/112631: One bacterail culture is 18 days older than a second bacterial culture. In 10 days the first culture will be twice the age of the second. Find the present age of the two cultures. x= age of second culture x+10= age of second culturte in 10 days x+18= age of first culture x+18+10= age of first culture in 10 days1 solutions Answer 82104 by scott8148(6628)   on 2007-11-26 22:13:03 (Show Source): You can put this solution on YOUR website!good setup equations "In 10 days the first culture will be twice the age of the second" 2(x+10)=x+18+10
 Exponents/112521: I am not really sure how to get this in here correctly so please bear with me. (y to the 5th power)to the 3rd power(y to the 3rd power)to the 2nd power Over (y to the 4th power)to the 4th power1 solutions Answer 82084 by scott8148(6628)   on 2007-11-26 20:04:57 (Show Source): You can put this solution on YOUR website!if the base value is the same ___ powers raised to powers are multiplied powers times powers are added ___ powers divided by powers are subtracted ___ ___ ___
 Linear_Equations_And_Systems_Word_Problems/112484: You invited 56 people to your graduation party. You can afford to rent 5 tables, round and/or rectangular(each costing the same). Each round table can seat 8 people and each rectangular table can seat 12 people. How many round and rectangular tables should you rent? .... I just dont know where to start, i'm pretty sure i need to use linear combination. it would help if you showed me how to do it, it is killing me not knowing waht to do. thank you very much hopefully you get it1 solutions Answer 82051 by scott8148(6628)   on 2007-11-26 18:13:46 (Show Source): You can put this solution on YOUR website!let x=round, so 5-x=rectangular 8(x)+12(5-x)=56 ___ 8x+60-12x=56
 real-numbers/112404: Has this been done correctly? -1/2 - (-5/8) = -1/2 + (+5/8) = 4/6 = 2/3 Fractions really confuse me and this real number sutracting is just as bad!!!Thanks so much for your time and help.1 solutions Answer 82013 by scott8148(6628)   on 2007-11-26 11:50:03 (Show Source): You can put this solution on YOUR website!to subtract (or add) fractions; the fractions must have the same denominator (bottom) ___ you subtract (or add) the numerators (top) you got the sign changes right but -1/2 should be -4/8 ___ then work with just the numerators
 Miscellaneous_Word_Problems/112308: This question is from textbook George has two investments that yield a total of \$185.60 in annual interest. The amount invested at 8% is \$320 less than twice the amount invested at 6%. How much is invested at each rate. Amount invested at 8%= Amount invested at 6%=1 solutions Answer 81951 by scott8148(6628)   on 2007-11-25 20:55:25 (Show Source): You can put this solution on YOUR website!let x="amount @ 6%", so 2x-320="amount @ 8%" (6%)x+(8%)(2x-320)=185.6 ___ .06x+.16x-25.6=185.6 ___ .22x=211.2
 Expressions-with-variables/112214: The sum of the lengths of one side of a right triangle and the hypotenuse is 20 cm. The other leg is 5 cm shorter than the hypotenuse. Find the length of each side. 1 solutions Answer 81949 by scott8148(6628)   on 2007-11-25 20:43:00 (Show Source): You can put this solution on YOUR website!let x=hypotenuse, so 20-x="one side" and x-5="other side" by Pythagoras, (20-x)^2+(x-5)^2=x^2 ___ 400-40x+x^2+x^2-10x+25=x^2 x^2-50x+425=0 ___ use quadratic formula to find x
 Expressions-with-variables/112215: One leg of a right triangle is 2 ft longer than the shorter side. If the length of the hypotenuse is 18 ft, how long is each leg? 1 solutions Answer 81947 by scott8148(6628)   on 2007-11-25 20:32:52 (Show Source): You can put this solution on YOUR website!let x="shorter side", so x+2="longer side" by Pythagoras, x^2+(x+2)^2=18^2 ___ 2x^2+4x-320=0 x^2+2x-160=0 ___ use the quadratic formula to find x
 Geometric_formulas/112219: If planes a and b are distinct planes having points x,y,and z in common, what conclusion can you make about points x,y, and z? Why?1 solutions Answer 81944 by scott8148(6628)   on 2007-11-25 20:19:06 (Show Source): You can put this solution on YOUR website!the intersection of two distinct planes results in a line if x, y, and are common to both planes; then x, y, an z are colinear (all on the same line)
 Circles/112226: Circle J has a radius of 6 in. Radii JK and JL form an angle that is not a straight angle. The length of KL is not 6in. Classify JKL according to its sides.Make a diagram if possible. Thanks a whole lot!1 solutions Answer 81943 by scott8148(6628)   on 2007-11-25 20:12:40 (Show Source): You can put this solution on YOUR website!a triangle with 2 sides equal (JK and JL) is called isosceles if KL had been 6, then it would be equilateral
 logarithm/112246: Solve, for x, the equation log base 2 (5x^2-x-2) = 2+2 log base 2 of x Thanks so much!1 solutions Answer 81937 by scott8148(6628)   on 2007-11-25 20:06:59 (Show Source): You can put this solution on YOUR website!using rules of logarithms; 5x^2-x-2=4x^2 x^2-x-2=0 ___ (x+1)(x-2)=0 remember, logarithms are NOT defined for negative numbers
 Complex_Numbers/112257: This question is from textbook Precalculus Graphical Numerical Algebraic given that 1+3i is a zero of f(x)= x^4-2x^3+5x^2+10x-50 find all zeros and write a linear factorization1 solutions Answer 81932 by scott8148(6628)   on 2007-11-25 19:56:35 (Show Source): You can put this solution on YOUR website!if 1+3i is a zero (root) then (x-1-3i) is a factor since complex roots occur in conjugate pairs, (x-1+3i) is also a factor so (x-1-3i)(x-1+3i) or x^2-2x+10 is a factor (x^4-2x^3+5x^2+10x-50)/(x^2-2x+10)=x^2-5 this gives (x+sqrt(5)) and (x-sqrt(5)) as the two other factors
 Average/112262: Angela's average for six math test is 87. On her first four test she had scores of 93, 87, 82, and 86. On her last test, she scores 4 points lower than she did on her fifth test.What scores did angela receive on her fifth and sixth tests/1 solutions Answer 81930 by scott8148(6628)   on 2007-11-25 19:41:22 (Show Source): You can put this solution on YOUR website!let x="6th test", so x+4="5th test" 93+87+82+86+x+4+x=6*87
 logarithm/112282: Please help me the question says use the Laws of Logarithms to rewrite the expression form with no logarithm of a product, quotient, or power. the problem is log(x/3square root of 1-x)1 solutions Answer 81927 by scott8148(6628)   on 2007-11-25 19:34:13 (Show Source): You can put this solution on YOUR website!multiplication and division means adding and subtracting logs exponents (powers and roots) means multiplying the log by the exponent log(x)-(log(3)+(1/2)log(1-x))
 Linear-equations/112303: The equation y = 14x – 80 describes the amount of money a class of students might earn from candy bar sales. What are the slope and y-intercept of this line?1 solutions Answer 81924 by scott8148(6628)   on 2007-11-25 19:26:46 (Show Source): You can put this solution on YOUR website!this is already in slope-intercept form ___ y=mx+b where m is the slope and b is the y-intercept
 Linear_Equations_And_Systems_Word_Problems/112292: hey hi, A theatre seats 2000 people and charges \$10 for a ticket. At this price, all the tickets can be sold. A survey indicates that if the ticket price is increased, the number sold will decrease by 100 for every dollar of increase. what ticket price would result in the greatest revenue? And thank you. i will be waiting!1 solutions Answer 81923 by scott8148(6628)   on 2007-11-25 19:24:29 (Show Source): You can put this solution on YOUR website!revenue=(tickets)*(price) ___ let x="price increase" r=(2000-100x)(10+x) ___ r=20000+1000x-100x^2 the graph of this is a downward opening parabola ___ the maximum is on the axis of symmetry x=-b/2a ___ x=-1000/((2)(-100)) if you want, you can find the revenue by substituting the x value into the r equation
 Polynomials-and-rational-expressions/112291: A company specializing in magazine sales over the telephone found that in 2500 phone calls, 360 resulted in sales and were made by male callers, and 480 resulted in sales and were made by female callers. If the company gets twice as many sales per call with a woman's voice than with a man's voice, then how many of the 2500 calls were made by females? I got stuck with this one too. I started an equation but I don't think it's right. I have 2500/360 = 6.95 and 2500/480 = 5.21. I'm not sure that this is right and I don't know where to go from here?1 solutions Answer 81920 by scott8148(6628)   on 2007-11-25 19:10:34 (Show Source): You can put this solution on YOUR website!let x="female calls", so 2500-x="male calls" 480/x=2(360/(2500-x)) ___ 480(2500-x)=720x ___ 2(2500-x)=3x
 Quadratic_Equations/111699: The path of a falling object is given by the function s = -16t + vt + st where v represents the initial velocity in ft/sec and s represents the initial height in feet. A.) If a rock is thrown upward with an initial velocity of 64 feet per second from the top of a 25-foot building, write the height (s) equation using this information. B.) How high is the rock after 1 second? C.) After how many seconds will the graph reach maximum height? D.) What is the maximum height?1 solutions Answer 81658 by scott8148(6628)   on 2007-11-23 21:34:54 (Show Source): You can put this solution on YOUR website!a. plug in the given values for v and s b. using the equation from a., plug in 1 for t and find s c. the graph of the equation (a) is a downward opening parabola ___ the maximum height is at the vertex, which lies on the axis of symmetry ___ the equation for the axis of symmetry is t=-b/2a ___ (where a is the coefficient of the t^2 term and b is the coefficient of the t term) d. plug the result from c. into the equation (a) to find s
 logarithm/111751: please help. ln x - ln(x-5)=ln 12 Round to three significant digits.1 solutions Answer 81657 by scott8148(6628)   on 2007-11-23 21:28:37 (Show Source): You can put this solution on YOUR website!x/(x-5)=12 ___ x=12x-60
 logarithm/111756: find x rounded to three significant digits. when I put this in the calculator it said .0128 would that be correct?1 solutions Answer 81655 by scott8148(6628)   on 2007-11-23 21:23:48 (Show Source): You can put this solution on YOUR website!yes
 Miscellaneous_Word_Problems/111786: Masonry: A 20ft ladder leans against a building at a 65 degree angle with the ground. Will it reach a window 17 ft above the ground? 1 solutions Answer 81654 by scott8148(6628)   on 2007-11-23 21:20:11 (Show Source): You can put this solution on YOUR website!let x="height of ladder" the ladder (20 ft) is the hypotenuse of a right triangle formed by the ladder, the building, and the ground the height of the ladder (x) divided by the length of the ladder (20) is the sine of the 65° angle so, x=(20)(sin65)
 Expressions-with-variables/111800: Factor Completely: ax-bx+5a-5b 6x(2)-26x-20 This shoul read 6x squared 25x2-40+16 This should read 25x squared x4-3x2-4 This should read x t the 4th adnd 3x squared1 solutions Answer 81653 by scott8148(6628)   on 2007-11-23 21:10:45 (Show Source): You can put this solution on YOUR website!(x+5)(a-b) 2(3x^2-13x-10) ___ 2(3x+2)(x-5) 25x^2-40x+16 ___ (5x-4)(5x-4) (x^2-4)(x^2+1) ___ (x+2)(x-2)(x^2+1)
 Polynomials-and-rational-expressions/111911: I need to completely factor out this problem. can anyone help me? 3x^4 + 6x^3 + 5x^3 + 10x^21 solutions Answer 81650 by scott8148(6628)   on 2007-11-23 21:01:08 (Show Source): You can put this solution on YOUR website!x^2(3x^2+6x+5x+10) ___ x^2(3x+5)(x+2)
 Travel_Word_Problems/111882: Could you please help me solve this problem. Thanks in advance. In a Grand Prix automobile race, Rapid Robert averaged 90 mph for the first half of the course and 110 mph for the second half of the course. Steady Eddy maintained a constant speed of 100 mph throughout the race. Who won the race? 1 solutions Answer 81649 by scott8148(6628)   on 2007-11-23 20:58:33 (Show Source): You can put this solution on YOUR website!the one who finishes first (shortest time) wins ___ let 2x="course distance" time=distance/rate RR ___ t=(x/90)+(x/110)=(11x/990)+(9x/990)=(20/990)x=(200/9900)x SE ___ t=2x/100=(198/9900)x
 Graphs/111896: Can you help me with this problem? The linear equation y=5 graphs as a horizontal/vertical/diagonal line (choose the correct label and show the work)1 solutions Answer 81648 by scott8148(6628)   on 2007-11-23 20:46:03 (Show Source): You can put this solution on YOUR website!writing in slope-intercept form ___ y=0(x)+5 zero slope means horizontal line
 logarithm/111897: help! When I put this into my calculator it said "0" solve for x 7e^5x=125 I put in 7 2nd Ln ^(5x)=125 (into a TI 83) what am I doing wrong? What should the answer be?1 solutions Answer 81647 by scott8148(6628)   on 2007-11-23 20:42:13 (Show Source): You can put this solution on YOUR website!not sure about TI 83 keystrokes... dividing by 7 gives e^(5x)=125/7 taking natural log gives 5x=ln(125/7) dividing by 5 gives x=(ln(125/7))/5
 logarithm/111902: Help! I am not familiar with a TI 83. I need to give four ordered pairs for this, y = 7^x I had x values of -15, 0, 15, and 30. The y values that showed up I did not understand, it said 2E-13, 1, 4.7E12, and 2.3E25 Why does it have E?1 solutions Answer 81646 by scott8148(6628)   on 2007-11-23 20:36:35 (Show Source): You can put this solution on YOUR website!you're raising 7 to the power of x, so you might want to pick more reasonable x values the E is shorthand for scientific notation ___ En is the same as X 10^n 1200 = 1.2 X 10^3 = 1.2E3
 logarithm/111905: Help. 4 log base of 5 (x+3)-3log base of 5 w write as a single expression.1 solutions Answer 81645 by scott8148(6628)   on 2007-11-23 20:28:54 (Show Source): You can put this solution on YOUR website!multiplying logs is exponentiation, subtracting logs is dividing log5(((x+3)^4)/(w^3))
 Finance/111904: This question is from textbook practical business math procedures Could someone please help me with this problem. I have been struggling for hours with it? By conversion of the markup formula, solve the following (round to the nearest whole percent as needed) 1. Percentage markup on cost=12.4% what is the percent markup on selling price? 2. Percentage markup on selling price= 13%. What is the percent markup on cost? Thanks in advance for your help!1 solutions Answer 81644 by scott8148(6628)   on 2007-11-23 20:25:03 (Show Source): You can put this solution on YOUR website!cost+markup=selling price 1. m=.124c ___ c+.124c=s ___ 1.124c=s ___ m/s = .124c/1.124c = .124/1.124 2. m=.13s ___ c+.13s=s ___ c=.87s ___ m/c = .13s/.87s = .13/.87
 Numbers_Word_Problems/111888: Could you please help me with this problem. Thanks in advance. What is the remainder when 3 to the power 777777 is divided by 7. 1 solutions Answer 81641 by scott8148(6628)   on 2007-11-23 19:27:24 (Show Source): You can put this solution on YOUR website!3^0 ___ 1 _____ R/7=1 3^1 ___ 3 _____ R/7=3 3^2 ___ 9 _____ R/7=2 3^3 ___ 27 _____ R/7=6 3^4 ___ 81 _____ R/7=4 3^5 ___ 243 _____ R/7=5 3^6 ___ 729 _____ R/7=1 3^7 ___ 2187 _____ R/7=3 3^8 ___ 6561 _____ R/7=2 3^9 ___ 19683 _____ R/7=6 3^10 ___ 59049 _____ R/7=4 3^11 ___ 177147 _____ R/7=5 the remainder pattern repeats every six powers 777777/6=129629 R3; so the remainder for (3^777777)/7 is 6
 Linear_Equations_And_Systems_Word_Problems/111883: the path of a falling object is given by the fuction s=-16t^2+v0t+s0 where v0 represents the initial velocityin ft/sec and s0 represents the initial height in feet.(the 0's are realy below the v and s ,i couldn't write them below them.) a. if a rock is thrown upward with an initial velocity of 64 feet per second from the top of a 25-foot building, write the equation using this information. b. how high is the rock after 1 second? c.after how many seconds will the graph reach maximum height? d. What is the maximum height?1 solutions Answer 81627 by scott8148(6628)   on 2007-11-23 17:44:26 (Show Source): You can put this solution on YOUR website!a. plug in the given values for v0 and s0 b. using the equation from a., plug in 1 for t and find s c. the graph of the equation (a) is a downward opening parabola ___ the maximum height is at the vertex, which lies on the axis of symmetry ___ the equation for the axis of symmetry is t=-b/2a ___ (where a is the coefficient of the t^2 term and b is the coefficient of the t term) d. plug the result from c. into the equation (a) to find s
 Travel_Word_Problems/111881: Could you please help me solve this problem. Thank you in advance. An object moved in one direction for 8 seconds at a constant speed. It reversed direction for 3 seconds with its rate doubled and then reversed direction again for 1 second at 40% of its initial speed. Find the three speeds if the object was 9.6 m from its start at the end of 12 seconds. 1 solutions Answer 81624 by scott8148(6628)   on 2007-11-23 17:22:20 (Show Source): You can put this solution on YOUR website!let x="first speed", so 2x="second speed" and .4x="third speed" 8(x)-3(2x)+1(.4x)=9.6