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# Recent problems solved by 'nerdybill'

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 test/556258: find the slope-intercept form of the line passing through the point (-7, 9) and parallel to the line 9x-7y=-31 solutions Answer 362095 by nerdybill(6951)   on 2012-01-12 10:55:41 (Show Source): You can put this solution on YOUR website!find the slope-intercept form of the line passing through the point (-7, 9) and parallel to the line 9x-7y=-3 . First, determine slope of: 9x-7y=-3 -7y=-9x-3 7y = 9x+3 y = (9/7)x + 3/7 slope is 9/7 . a line parallel must have the same slope. use the slope (9/7) and the given point (-7,9) and plug into the "point-slope" form: y - y1 = m(x - x1) y - 9 = (9/7)(x - (-7)) y - 9 = (9/7)(x + 7) y - 9 = (9/7)x + 9 y = (9/7)x + 9 + 9 y = (9/7)x + 18 (this is what they're looking for -- in "slope-intercept" form)
 Functions/555718: find the domain and range of a relation {(-2,4), (1,-3), (3,-1), (5,-6)}1 solutions Answer 361916 by nerdybill(6951)   on 2012-01-11 14:33:09 (Show Source): You can put this solution on YOUR website!find the domain and range of a relation {(-2,4), (1,-3), (3,-1), (5,-6)} domain are the x values: domain: {-2, 1, 3, 5} . range are the y values: range: {4, -3, -1, -6} you could arrange the above in sequential order: range: {-6, -3, -1, 4}
 Equations/555661: FACTOR THE TRINOMIAL COMPLETELY: x^2 + x-2 =1 solutions Answer 361886 by nerdybill(6951)   on 2012-01-11 11:47:49 (Show Source): You can put this solution on YOUR website!x^2 + x-2 (x+2)(x-1)
 Evaluation_Word_Problems/555266: Please help solv. A digital photgraph is 30 pixel longer than it is wide and has a total area of 4000 pixels. Find the dimensions of this photograph.1 solutions Answer 361716 by nerdybill(6951)   on 2012-01-10 16:53:44 (Show Source): You can put this solution on YOUR website!Please help solv. A digital photgraph is 30 pixel longer than it is wide and has a total area of 4000 pixels. Find the dimensions of this photograph. Let x = width (in pixels) then x+30 = length . x(x+30) = 4000 x^2+30x = 4000 x^2+30x-4000 = 0 (x+80)(x-50) = 0 x = {-80, 50} throw out the negative solution leaving: x = 50 pixels (width) . Length: x+30 = 50+30 = 80 pixels . Dimensions: 50 by 80 pixels
 Length-and-distance/555259: If the minute hand of a big clock is 1.2 cm long, how far does the tip of the minute hands move in 20 minutes?1 solutions Answer 361706 by nerdybill(6951)   on 2012-01-10 16:31:30 (Show Source): You can put this solution on YOUR website!If the minute hand of a big clock is 1.2 cm long, how far does the tip of the minute hands move in 20 minutes? Since circumference of a circle made by the tip of the minute hand is: 2(pi)r 2(3.14)1.2 7.536 cm . if it travels 20 minutes, that is: 20/60 of the circle or 1/3 of circle . Distance travel is then: (1/3)(7.536) = 2.512 cm
 Quadratic_Equations/555153: Okay I started an internet college algebra class, and I'm kicking myself for it! My website will not allow me to watch clips on solving problems... so I need help on figuring this problem due to I have 5 more just like it. Any help would be appreciated. Here's my problem: x=3 and Y=-2 [X]+[Y]=? If someone could tell me what kind of math problem is called it would be appreciated!!! 1 solutions Answer 361656 by nerdybill(6951)   on 2012-01-10 12:51:47 (Show Source): You can put this solution on YOUR website!Given: x=3 and Y=-2 |X| +|Y|=? . Plug in the given values: |3| +|-2| (notice: absolute value of -2 is 2) 3 + 2 5 (this is your answer)
 Linear-equations/553571: What is the equation of the line that passes through (1, 2) and is parallel to the line whose equation is 2x + y - 1 = 0? 2x - y - 4 = 0 2x + y - 4 = 0 2x + y + 4 = 01 solutions Answer 360942 by nerdybill(6951)   on 2012-01-06 17:00:04 (Show Source): You can put this solution on YOUR website!What is the equation of the line that passes through (1, 2) and is parallel to the line whose equation is 2x + y - 1 = 0? put: 2x + y - 1 = 0 into "slope-intercept" form: 2x + y - 1 = 0 2x + y = 1 y = -2x + 1 now, we know the slope is -2 "parallel" lines must have the same slope use -2 and (1,2) to populate "point-slope" form: y - y1 = m(x - x1) y - 2 = -2(x - 1) y - 2 = -2x + 2 y = -2x + 4 (slope-intercept form) 2x + y -4 = 0 (standard form) (answer)
 Equations/553559: Solve the following equation by using FOIL: x^2-2x-35=01 solutions Answer 360923 by nerdybill(6951)   on 2012-01-06 16:02:47 (Show Source): You can put this solution on YOUR website!Solve the following equation by using FOIL: x^2-2x-35=0 Factoring (reverse FOIL) we get: (x+5)(x-7) = 0 x = {-5, 7}
 Number-Line/553464: what is -25 + 47 ? does it equal negative 22 or just 22 ?1 solutions Answer 360857 by nerdybill(6951)   on 2012-01-06 09:34:29 (Show Source): You can put this solution on YOUR website!It would be just 22
 Graphs/553159: They want me to draw a rectangle with 22 square units inside it--that's the problem, but it seems like a trick because you cannot do it. it doesn't even out. Pls help!1 solutions Answer 360716 by nerdybill(6951)   on 2012-01-05 17:04:37 (Show Source): You can put this solution on YOUR website!They want me to draw a rectangle with 22 square units inside it--that's the problem, but it seems like a trick because you cannot do it. it doesn't even out. Pls help! Remember, it's a rectangle... how about a rectangle that is 2 units wide and 11 units long (this is equivalent to 22 square units)
 Exponents-negative-and-fractional/553118: How do I write 8^-9 as a positive exponent?1 solutions Answer 360690 by nerdybill(6951)   on 2012-01-05 16:13:02 (Show Source): You can put this solution on YOUR website!How do I write 8^-9 as a positive exponent? By moving the term to the denominator: would be equivalent to:
 Equations/553107: Hi can you please help me solve; I added all three number then divide, what do I do after that? Jacqui has gradess of 88 and 77 on her first two algebra tests. If she wants an average of at least 71, what possible scores can she make on her third test? Thank you...1 solutions Answer 360681 by nerdybill(6951)   on 2012-01-05 15:47:24 (Show Source): You can put this solution on YOUR website!Jacqui has gradess of 88 and 77 on her first two algebra tests. If she wants an average of at least 71, what possible scores can she make on her third test? Let x = score of third test then (88+77+x)/3 >= 71 (165+x)/3 >= 71 165+x >= 213 x >= 213-165 x >= 48 she must have a score of 48 or greater
 Square-cubic-other-roots/553000: Use the difference-of-squares pattern to factor. x^6 - 9y^2 = Comment: I'm having trouble figuring out how to factor the x^6 , none of the examples in the chapter have none square x values. also, none of the rules describe how to do it with x^6. Thank you, Anthony1 solutions Answer 360597 by nerdybill(6951)   on 2012-01-05 09:14:38 (Show Source): You can put this solution on YOUR website!x^6 - 9y^2 notice we can rewrite as: (x^3)^2 - (3y)^2 now, we have a difference of squares which factors to: (x^3 - 3y)(x^3 + 3y)
 percentage/553001: 254 of my patients got vaccinated of the 360 total we have. What percentage of patients were vaccinated? 1 solutions Answer 360596 by nerdybill(6951)   on 2012-01-05 09:13:04 (Show Source): You can put this solution on YOUR website!254 of my patients got vaccinated of the 360 total we have. What percentage of patients were vaccinated? 254/360 * 100 254/360 * 100 0.71 * 100 71%
 Average/552183: Please help me solve this problem. Jamyce has received grades of 89, 92, and 85 on 3 tests. What grade must she get on the next test in order to have an average of 90? 89+92+85= 266 266/3 = 88.6666... What is the next step? 1 solutions Answer 360166 by nerdybill(6951)   on 2012-01-03 14:27:37 (Show Source): You can put this solution on YOUR website!Let x = score on fourth test then (89+92+85+x)/4 = 90 (266+x)/4 = 90 (266+x) = 360 x = 360-266 x = 94
 Travel_Word_Problems/551863: How far can a car travel in 40 minutes if it is traveling at an average speed of 50 miles per hour?1 solutions Answer 359975 by nerdybill(6951)   on 2012-01-02 15:49:22 (Show Source): You can put this solution on YOUR website! How far can a car travel in 40 minutes if it is traveling at an average speed of 50 miles per hour? apply distance formula: d = rt d = 50(40/60) d = 50(4/6) d = 50(2/3) d = 100/3 d = 33.3 miles
 Angles/551746: what is the complement to an angle that measures 71 degrees? 1 solutions Answer 359866 by nerdybill(6951)   on 2012-01-02 11:29:17 (Show Source): You can put this solution on YOUR website!what is the complement to an angle that measures 71 degrees? if two angles are "complement" the sum is 90 degrees Let x = complement to the angle then 71+x = 90 x = 90-71 x = 19 degrees (answer)
 Equations/551577: log(x+5)= -1 What does x equal?1 solutions Answer 359813 by nerdybill(6951)   on 2012-01-02 01:34:38 (Show Source): You can put this solution on YOUR website!log(x+5)= -1 What does x equal? . starting with: log(x+5)= -1 (x+5)= 10^(-1) x+5= 1/10^(1) x+5= 1/10 x = 1/10 - 5 x = 1/10 - 50/10 x = -49/10 x = -4.9
 Average/551642: If x=2y and 8y=z, what is X in terms of z? THANK YOU AND GOD BLESS YOU!=)1 solutions Answer 359812 by nerdybill(6951)   on 2012-01-02 01:30:39 (Show Source): You can put this solution on YOUR website!If x=2y and 8y=z, what is X in terms of z? . Since: 8y=z solving for y, we get: y = z/8 . Substitute above into: x=2y x=2(z/8) x=z/4 (this is what they're looking for)
 Rational-functions/551596: F(x)=x^2-3x g(x)=2x+4 What is the value of: F(g^-1(-4)) Can you please help me with this problem? I am having trouble with functions. 1 solutions Answer 359811 by nerdybill(6951)   on 2012-01-02 01:28:40 (Show Source): You can put this solution on YOUR website!F(x)=x^2-3x g(x)=2x+4 What is the value of: F(g^-1(-4)) . Begin by finding:g^-1(x) g(x)=2x+4 y=2x+4 switch the variables and solve for y: x=2y+4 x-4=2y x/2 - 2 = y (this is g^-1(x)) . Now, find: g^-1(-4) = 4/2 - 2 g^-1(-4) = 2 - 2 g^-1(-4) = 0 . Finally, we can find: F(g^-1(-4)) F(0) F(0)=0^2-30 = 0-0 = 0 . Solution: 0
 �t�e�s�t/551635: housewife wishes to mix coffee beans worth Php60 and Php85 a kilogram to obtain 50 kilograms of coffee beans worth Php70 a kilogram. How many kilograms of each should she use?1 solutions Answer 359810 by nerdybill(6951)   on 2012-01-02 01:23:50 (Show Source): You can put this solution on YOUR website!housewife wishes to mix coffee beans worth Php60 and Php85 a kilogram to obtain 50 kilograms of coffee beans worth Php70 a kilogram. How many kilograms of each should she use? Let x = amount (kilograms) of Php60 coffee beans then 50-x = amount (kilograms) of Php85 coffee beans . 60x + 85(50-x) = 70(50) 60x + 4250-85x = 3500 4250-25x = 3500 -25x = 3500-4250 -25x = -750 x = 30 kilograms of Php60 coffee beans . Php85 coffee beans: 50-x = 50-30 = 20 kilograms
 test/551416: Roberto is ordering rings from a catolog. There is a shipping charge of \$5 no matter how many rings are bought. Each ring costs \$6.If roberto spends \$71, how many rings does he order?1 solutions Answer 359716 by nerdybill(6951)   on 2012-01-01 12:21:38 (Show Source): You can put this solution on YOUR website!Roberto is ordering rings from a catolog. There is a shipping charge of \$5 no matter how many rings are bought. Each ring costs \$6.If roberto spends \$71, how many rings does he order? Let n = number of rings ordered then 6n + 5 = 71 6n = 66 n = 11 rings
 Travel_Word_Problems/551379: two cyclists start toward each other from two towns that are 46 km apart. one cyclist rides at 9 km per hour and the other rides at 14 km per hour. in how many hours will they meet?1 solutions Answer 359695 by nerdybill(6951)   on 2012-01-01 07:11:13 (Show Source): You can put this solution on YOUR website! two cyclists start toward each other from two towns that are 46 km apart. one cyclist rides at 9 km per hour and the other rides at 14 km per hour. in how many hours will they meet? . Apply the distance formula of d=rt: Let x = number of hours when they meet then 9x + 14x = 46 23x = 46 x = 46/23 x = 2 hours
 Numbers_Word_Problems/551373: if the length of the rectangle is one foot less than the width and the area is 12ft squared ,find the dimensions. 1 solutions Answer 359694 by nerdybill(6951)   on 2012-01-01 07:09:03 (Show Source): You can put this solution on YOUR website!if the length of the rectangle is one foot less than the width and the area is 12ft squared ,find the dimensions. . Let w = width then w-1 = length . w(w-1) = 12 w^2-w = 12 w^2-w-12=0 factoring: (w+3)(w-4) = 0 w = {-3,4} throw out the -3 leaving: w = 4 feet (width) . Length: w-1 = 4-1 = 3 feet (length) . solution: 4 feet by 3 feet
 Rectangles/551378: the perimiter of a rectangle is 40 meters. Its width is 8 meters. what is its length1 solutions Answer 359692 by nerdybill(6951)   on 2012-01-01 06:53:01 (Show Source): You can put this solution on YOUR website! the perimiter of a rectangle is 40 meters. Its width is 8 meters. what is its length . Let x = length then 2(x+8) = 40 dividing both sides by 2: (x+8) = 20 subtracting 8 from both sides: x = 12 meters
 Exponential-and-logarithmic-functions/551354: The half-life of a certain radioactive material is 85 days. An initial amount of material has a mass of 801 kg. Write an exponential function that models the decay of this material.1 solutions Answer 359668 by nerdybill(6951)   on 2011-12-31 22:59:20 (Show Source): You can put this solution on YOUR website!exponential delay form: N = Noe^(kt) where N is amount after time t No is initial amount k is a constant (<0) . The half-life of a certain radioactive material is 85 days. An initial amount of material has a mass of 801 kg. Write an exponential function that models the decay of this material. . Here, all we need to do is the define 'k' -- do this with the info provided and plug into: N = Noe^(kt) (1/2)(801) = 801e^(k*85) dividing both sides by 801: (1/2) = e^(k*85) ln(1/2) = k*85 ln(1/2)/85 = k -.0082 = k . So, the exponential decay model is N = 801e^(-.0082t)
 Graphs/551277: The Parallel Line To y=7x+4 Through (-8,-3)1 solutions Answer 359665 by nerdybill(6951)   on 2011-12-31 22:47:29 (Show Source): You can put this solution on YOUR website!The Parallel Line To y=7x+4 Through (-8,-3) . Slope of: y=7x+4 is 7 A line "parallel" to this must have the same slope (7). . Use the slope (7) and the given point (-8, -3) and plug into the "point-slope" form: y - y1 = m(x - x1) y - (-3) = 7(x - (-8)) y + 3 = 7(x + 8) y + 3 = 7x + 56 y = 7x + 53 (this is what they're looking for)
 Rate-of-work-word-problems/551352: A Painter can do a given job in 6hours. Her helper can do the same job in 10 hours. The painter begins the work and after two hours is joined by the helper. In how many hours will the complete the job? Please, thank you~ Happy New Year to you, Great Tutors! <31 solutions Answer 359663 by nerdybill(6951)   on 2011-12-31 22:43:28 (Show Source): You can put this solution on YOUR website!A Painter can do a given job in 6hours. Her helper can do the same job in 10 hours. The painter begins the work and after two hours is joined by the helper. In how many hours will the complete the job? . Let x = time (hours) worked by Painter (also to complete job) then x-2 = hours worked by helper . x(1/6) + (x-2)(1/10) = 1 multiplying both sides by 60: x(10) + (x-2)(6) = 60 10x + 6x-12 = 60 16x - 12 = 60 16x = 72 x = 72/16 x = 4.5 hours
 Angles/551316: Angle N is 18 degrees less than twice it's supplement1 solutions Answer 359650 by nerdybill(6951)   on 2011-12-31 20:47:41 (Show Source): You can put this solution on YOUR website! Angle N is 18 degrees less than twice it's supplement Let N = measure of angle N then 180-N = supplement of N . and from: "Angle N is 18 degrees less than twice it's supplement" N = 2(180-N) - 18 N = 360-2N - 18 N = 342-2N 3N = 342 N = 114 degrees
 Polynomials-and-rational-expressions/551225: The profit P, of a video company (in thousands of dollars) is given by P(x) = -5x^2+550x-5000. X is the amount spend on advertising in thousands of dollars. Determine the amount spent on advertising that will result in a profit of \$0. Describe the relationship and the graph of P(x) I think you need to factor P(x)=5x^2+50x(11-x)- 50x(100-x) I really do not know how to factor that 1 solutions Answer 359575 by nerdybill(6951)   on 2011-12-31 13:15:43 (Show Source): You can put this solution on YOUR website!Starting with: P(x) = -5x^2+550x-5000 since profit is zero, replace P(x) with a zero: 0 = -5x^2+550x-5000 multiply both sides by -1: 0 = 5x^2-550x+5000 divide both sides by 5: 0 = x^2-110x+1000 factoring: 0 = (x-10)(x-100) x = {10,100} two solutions: \$10 and \$100