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Recent problems solved by 'nerdybill'

nerdybill answered: 6961 problems
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Inverses/477037: if a number is subtracted from twice its reciprocal, The result is -23/5.What is the number. 1 solutions Answer 327043 by nerdybill(6963)   on 2011-08-02 09:19:13 (Show Source): You can put this solution on YOUR website! if a number is subtracted from twice its reciprocal, The result is -23/5.What is the number. . Let x = the number then 1/x = the reciprocal . x - 2(1/x) = -23/5 x - 2/x = -23/5 multiplying both sides by 5x: 5x^2 - 10 = -23x 5x^2 + 23x - 10 = 0 (5x-2)(x+5) = 0 x = {2/5, -5} answer: -5

Square-cubic-other-roots/475889: What is the 5th root of -1/32? 1 solutions Answer 326370 by nerdybill(6963)   on 2011-07-29 23:00:12 (Show Source): You can put this solution on YOUR website! What is the 5th root of -1/32? Since: -1/32 can be written as: -1/2^5 the answer is: -1/2

Points-lines-and-rays/475391: Write the equation of the line in slope-intercept form with a slope of 3 and a y-intercept of -2. 1 solutions Answer 325991 by nerdybill(6963)   on 2011-07-28 10:04:44 (Show Source): You can put this solution on YOUR website! "Slope-intercept" form: y = mx + b where m is the slope b is the y-intercept . So, plugging in the given values we have: y = 3x + (-2) y = 3x - 2 (this is what they're looking for)

percentage/475346: if my total is $67.50 and there is a sales tax of 7% what is the total that i will be paying? 1 solutions Answer 325975 by nerdybill(6963)   on 2011-07-28 08:38:00 (Show Source): You can put this solution on YOUR website! 67.50 + .07(67.50) = 67.50 + 4.73 = $72.23

Graphs/475159: What is the y=mx+b form of "x-4y=12" 1 solutions Answer 325810 by nerdybill(6963)   on 2011-07-27 17:25:51 (Show Source): You can put this solution on YOUR website! What is the y=mx+b form of "x-4y=12" . starting with: x-4y=12 -4y=-x+12 4y=x-12 y=(1/4)x-3

Graphs/475086: write the equation of a line (in slope intercept form)/ that goes through (10,4) and has a slope of one-fifth 1 solutions Answer 325749 by nerdybill(6963)   on 2011-07-27 14:22:42 (Show Source): You can put this solution on YOUR website! write the equation of a line (in slope intercept form)/ that goes through (10,4) and has a slope of one-fifth . plug given info into "point-slope" form: y - y1 = m(x - x1) y - 4 = (1/5)(x - 10) y - 4 = (1/5)x - 2 y = (1/5)x + 2 (this is what they're looking for)

logarithm/475029: Use properties of logarithms to solve the equation log(base3)y – log(base3)7 = log(base3)2 1 solutions Answer 325735 by nerdybill(6963)   on 2011-07-27 12:21:37 (Show Source): You can put this solution on YOUR website! Use properties of logarithms to solve the equation log(base3)y – log(base3)7 = log(base3)2

Equations/474978: (x/12)-(5/6)=(x+6)/6 1 solutions Answer 325703 by nerdybill(6963)   on 2011-07-27 09:38:15 (Show Source): You can put this solution on YOUR website! (x/12)-(5/6)=(x+6)/6 multiplying both sides by 12: x - 10 = 2x + 12 -10 = x + 12 -22 = x

Linear-equations/474952: What is the equation of a line that passes through (7, -2) and has a slope of 3? 1 solutions Answer 325699 by nerdybill(6963)   on 2011-07-27 09:15:57 (Show Source): You can put this solution on YOUR website! What is the equation of a line that passes through (7, -2) and has a slope of 3? plug into "point-slope" form: y - y1 = m(x - x1) y - (-2) = 3(x - 7) y + 2 = 3x - 21 y = 3x - 23 (this is what they're looking for)

Linear-equations/474953: I need your help Solution A is 30% acid and solution B is 60% acid. How many gallons of each solution must be used to create a 60 gallons miture that is 50% acid? Thanks 1 solutions Answer 325696 by nerdybill(6963)   on 2011-07-27 08:57:38 (Show Source): You can put this solution on YOUR website! Solution A is 30% acid and solution B is 60% acid. How many gallons of each solution must be used to create a 60 gallons miture that is 50% acid? . Let x = amount (gal) of 30% then 60-x = amount of 60% . .30x + .60(60-x) = .50(60) .30x + 36-.60x = 30 36-.30x = 30 -.30x = -6 x = 20 gals of 30% acid . 60% acid: 60-x = 60-20 = 40 gals

Quadratic_Equations/474494: Solve using the Factoring method. 8x^2+19x=15 1 solutions Answer 325415 by nerdybill(6963)   on 2011-07-26 10:10:49 (Show Source): You can put this solution on YOUR website! 8x^2+19x=15 8x^2+19x-15 = 0 8x^2+8x-15x-15 = 0 (8x^2+8x)-(15x+15) = 0 8x(x+1)-15(x+1) = 0 (x+1)(8x-15) = 0 x = {-1, 15/8}

Polynomials-and-rational-expressions/474276: Factor Completely 81x^2 - 36y^2 1 solutions Answer 325281 by nerdybill(6963)   on 2011-07-25 18:08:09 (Show Source): You can put this solution on YOUR website! because we can rewrite: 81x^2 - 36y^2 as (9x)^2 - (6y)^2 It is a "difference of squares" (special factoring case): (9x - 6y)(9x + 6y)

Linear-equations/474135: how do I solve m = -5/7,(4,2) 1 solutions Answer 325175 by nerdybill(6963)   on 2011-07-25 12:30:12 (Show Source): You can put this solution on YOUR website! how do I solve m = -5/7,(4,2) . You don't really "solve" it... rather, you can derive the equation for the line where: m (slope) is -5/7 and it crosses point (4,2) . plug given info into the "point-slope" form: y - y1 = m(x - x1) y - 2 = (-5/7)(x - 4) y - 2 = (-5/7)x + 20/7 y = (-5/7)x + 20/7 + 2 y = (-5/7)x + 20/7 + 14/7 y = (-5/7)x + 34/7 (this is what they're looking for)

Coordinate-system/474084: Find the coordinates of the turning point of the curve (by expressing this equation in the form ) and determine the nature of this turning point. *Please answer as soon as possible bro :) 1 solutions Answer 325140 by nerdybill(6963)   on 2011-07-25 11:01:09 (Show Source): You can put this solution on YOUR website! "turning point" is at the vertex, where the x coordinate is at: x = -b/(2a) x = -4/(2(-1)) x = -4/(-2) x = 2 . find y by plugging it into equation: . turning point is at (2,10) Since the coefficient associated with the x^2 is negative, it is a parabola that opens downwards. This means (2,10) is the peak.

Angles/472859: Supplementary angles if 1 and 2 are supplementary angles and if the measure of 2 is 17 times the measure of 1, determine the measure of the two angles. 1 solutions Answer 324211 by nerdybill(6963)   on 2011-07-21 15:26:52 (Show Source): You can put this solution on YOUR website! Supplementary angles if 1 and 2 are supplementary angles and if the measure of 2 is 17 times the measure of 1, determine the measure of the two angles. . Let x = smaller angle then 17x = larger angle . x + 17x = 180 18x = 180 x = 10 degrees (one angle) . Other angle: 17x = 17(10) = 170 degrees

Equations/472841: Multiply (- x7) (-x) Help me answer this!! 1 solutions Answer 324207 by nerdybill(6963)   on 2011-07-21 15:11:29 (Show Source): You can put this solution on YOUR website! I'm assuming: The negative cancels each other leaving:

Triangles/472447: In an isosceles triangle, the length of each leg exceeds twice the base by 2 cm. The perimeter is 24. How long is each leg? 1 solutions Answer 323932 by nerdybill(6963)   on 2011-07-20 15:35:02 (Show Source): You can put this solution on YOUR website! In an isosceles triangle, the length of each leg exceeds twice the base by 2 cm. The perimeter is 24. How long is each leg? . Draw a diagram of the problem, it'll help you see the solution. Let b = length of base then 2b+2 = length of leg . 2(2b+2) + b = 24 4b+4 + b = 24 5b = 20 b = 4 cm (base) . length of the two legs: 2b+2 = 2(4)+2 = 10 cm

Functions/472459: how do i find the x intercept for y=-2x^2+7x-6 1 solutions Answer 323925 by nerdybill(6963)   on 2011-07-20 15:08:29 (Show Source): You can put this solution on YOUR website! y=-2x^2+7x-6 set y to 0 and solve for x: 0=-2x^2+7x-6 0= 2x^2-7x+6 0= (2x-3)(x-2) x = {3/2, 2} . so the two x-intercepts are at: (3/2, 0) and (2, 0)

Travel_Word_Problems/472462: Im so confused on how to set this question up.. Any help will be GREAT! If you are 2/7 mile from home and you can walk 3 5/7 mph, how long will it take you to get home? 1 solutions Answer 323924 by nerdybill(6963)   on 2011-07-20 15:04:53 (Show Source): You can put this solution on YOUR website! If you are 2/7 mile from home and you can walk 3 5/7 mph, how long will it take you to get home? start by converting 3 5/7 into an improper fraction: 3 + 5/7 = 21/7 + 5/7 = 26/7 mph . then apply distance formula: d = rt 2/7 = (26/7)t multiplying both sides by 7 2 = 26t 2/26 = t .077 hours = t or 4.6 minutes = t

Exponential-and-logarithmic-functions/472433: The initial population of a town is 127,866 and it grows with a doubling time of 12 years. What will the population be in 33 years? 1 solutions Answer 323915 by nerdybill(6963)   on 2011-07-20 14:22:30 (Show Source): You can put this solution on YOUR website! The initial population of a town is 127,866 and it grows with a doubling time of 12 years. What will the population be in 33 years? . assuming exponential growth: a = pe^(rt) first, we need to find r (rate of growth) 2(127866) = 127866e^(r*12) 2 = e^(r*12) ln(2) = 12r ln(2)/12 = r . Our general formula: a = 127866e^(ln(2)/12 * t) . subsitute 33 for t: a = 127866e^(ln(2)/12 * 33) a = 127866e^(1.9062) a = 127866(6.7272) a = 860176

Travel_Word_Problems/472431: If you are driving 47 mph how long in seconds will it take you to travel 17 miles? 1 solutions Answer 323913 by nerdybill(6963)   on 2011-07-20 14:15:02 (Show Source): You can put this solution on YOUR website! If you are driving 47 mph how long in seconds will it take you to travel 17 miles? applying distance formula: d = rt 17 = 47t 17/47 = t 0.362 hours = t in terms of seconds: 0.362*60*60 = 1302 seconds

Length-and-distance/471985: What is 5 3/4 inches minus 1/8 inch? 1 solutions Answer 323632 by nerdybill(6963)   on 2011-07-19 15:20:03 (Show Source): You can put this solution on YOUR website! What is 5 3/4 inches minus 1/8 inch? convert 3/4 to eighths: 3/4 * 2/2 = 6/8 6/8 - 1/8 = 5/8 answer: 5 and 5/8

Triangles/471874: the legs of a right triangle are 75 and 100 . what is the length of the hypotenuse 1 solutions Answer 323581 by nerdybill(6963)   on 2011-07-19 10:44:19 (Show Source): You can put this solution on YOUR website! the legs of a right triangle are 75 and 100 . what is the length of the hypotenuse apply Pythagorean theorem Let h = hypotenuse then h^2 = 75^2 + 100^2 h^2 = 5625 + 10000 h^2 = 15625 h = 125

Square-cubic-other-roots/471873: What does it mean to refer to a 20 inch t.v set or 25 inch t.v set. Such unit refer to the diagonal of the screen. A 20 inch set also has a width of 16 inches, what is the height? 1 solutions Answer 323580 by nerdybill(6963)   on 2011-07-19 10:42:08 (Show Source): You can put this solution on YOUR website! What does it mean to refer to a 20 inch t.v set or 25 inch t.v set. Such unit refer to the diagonal of the screen. A 20 inch set also has a width of 16 inches, what is the height? apply Pythagorean theorem: Let h = height then h^2 + 16^2 = 20^2 h^2 + 256 = 400 h^2 = 144 h = 12 inches

Travel_Word_Problems/471667: How far will you go doing 80 mph in 21 minutes? 1 solutions Answer 323479 by nerdybill(6963)   on 2011-07-18 20:26:45 (Show Source): You can put this solution on YOUR website! How far will you go doing 80 mph in 21 minutes? . Start by representing 21 minutes as hours: 21/60 hours . then, apply the distance formula: d = rt d = 80(21/60) d = 8(21/6) d = 4(21/3) d = 4(7) d = 28 miles

Money_Word_Problems/471490: If a hospital patient is given 50 milligrams of medicine which leaves the bloodstream at 10% per hour, how many milligrams of medicine will remain in the system after 6 hours? Use the function A(t) = Iert. 1 solutions Answer 323370 by nerdybill(6963)   on 2011-07-18 12:05:32 (Show Source): You can put this solution on YOUR website! If a hospital patient is given 50 milligrams of medicine which leaves the bloodstream at 10% per hour, how many milligrams of medicine will remain in the system after 6 hours? Use the function A(t) = Iert. . A(t) = Ie^(rt) A(6) = 50e^(-.10*6) A(6) = 50e^(-.60) A(6) = 50e^(-.60) A(6) = 27.44 milligrams

Angles/471483: If cutting a board 24" X 30 1/2" how do I find what the true 90deg angle messurment will be? 1 solutions Answer 323351 by nerdybill(6963)   on 2011-07-18 10:50:41 (Show Source): You can put this solution on YOUR website! I'm not sure I understand your question. However, if you want to make sure the corners are square (i.e. 90 degrees) then measure the two diagonals -- it should be exactly the same -- applies the Pythagorean theorem.

Complex_Numbers/471477: The _____ is the name of the number under the radical symbol in the quadratic formula. 1 solutions Answer 323344 by nerdybill(6963)   on 2011-07-18 10:26:48 (Show Source): You can put this solution on YOUR website! determinant

Linear-equations/471473: what is the slope of a line that is perpendicular to the graph of: y=-1/2x+4? 1 solutions Answer 323341 by nerdybill(6963)   on 2011-07-18 10:10:33 (Show Source): You can put this solution on YOUR website! since the slope of: y=-1/2x+4 is -1/2 . a line perpendicular to this must have a slope that is the "negative reciprocal": (-1/2)m = -1 (1/2)m = 1 m = 2 . answer is 2

Polynomials-and-rational-expressions/471347: X^2+3x-28 what is the factor of this trinomial 1 solutions Answer 323266 by nerdybill(6963)   on 2011-07-17 20:43:24 (Show Source): You can put this solution on YOUR website! X^2+3x-28 (x+7)(x-4)

logarithm/471118: (log16+2log2)/log4=x 1 solutions Answer 323145 by nerdybill(6963)   on 2011-07-17 08:53:23 (Show Source): You can put this solution on YOUR website! (log16+2log2)/log4=x (log16+log2^2)/log4=x (log16+log4)/log4=x (log16+log4)-log4=x log16=x 1.204 = x