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Recent problems solved by 'checkley75'

checkley75 answered: 3664 problems
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Polynomials-and-rational-expressions/177047: The half-life of Snowmanian-37 is 16 hours. How long will it take a quantity of Snowmanian-37 to reduce to 60% of its original mass? 1 solutions Answer 132144 by checkley75(3666)   on 2009-01-16 20:39:32 (Show Source): You can put this solution on YOUR website! 16(1-.60)=16*.4=6.4 hours.

Linear-equations/177053: how do i solve y=2x; x+2y=8 using substitution? 1 solutions Answer 132143 by checkley75(3666)   on 2009-01-16 20:36:41 (Show Source): You can put this solution on YOUR website! y=2x x+2y=8 replace y in the second equation with (2x) & solve for x x+2(2x)=8 x+4x=8 5x=8 x=8/5 ans. y=2*8/5 y=16/5 Proof: 8/5+2*16/5=8 8/5+32/5=8 40/5=8 8=8

Miscellaneous_Word_Problems/177072: This question is from textbook Mike invested $6000 for one year. He invested part of it at 9% and the rest at 11%. At the end of the year he earned $624 in interest. How much did he invest at each rate? 1 solutions Answer 132142 by checkley75(3666)   on 2009-01-16 20:30:49 (Show Source): You can put this solution on YOUR website! .11x+.09(6000-x)=624 .11x+540-.09x=624 .02x=624-540 .02x=84 x=84/.02 x=4,200 invested @ 11% 6,000-4,200=1,800 invested @ 9% Proof: .11*4,200+.09*1,800=624 462+162=624 624=624

Equations/177090: (5x2 + 7y - 6z2), (4y + 3x2), (2y - 2x2) all my problem says to do is add. I cant remember how to do this 1 solutions Answer 132140 by checkley75(3666)   on 2009-01-16 20:25:53 (Show Source): You can put this solution on YOUR website! 5x^2+7y-6z^2 3x^2+4y -2x^2+2y --------------------- 6x^2+13y-6z^2 ans.

Functions/176971: y=3x-4 1 solutions Answer 132029 by checkley75(3666)   on 2009-01-15 22:07:44 (Show Source): You can put this solution on YOUR website! If this is a line equation then: y=3x-4 (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, 3x-4).

Equations/176973: 8-3(x-4)=4 1 solutions Answer 132027 by checkley75(3666)   on 2009-01-15 22:04:17 (Show Source): You can put this solution on YOUR website! 8-3(x-4)=4 8-3x+12=4 -3x=4-8-12 -3x=-16 x=-16/-3 x=16/3 or 5 1/3 ans. Proof: 8-3(16/3-4)=4 8-3([16-12]/3)=4 8-3(4/3)=4 8-12/3=4 8-4=4 4=4

Graphs/176896: y=1/3x+3/2 1 solutions Answer 132024 by checkley75(3666)   on 2009-01-15 21:58:31 (Show Source): You can put this solution on YOUR website! y=1/3x+3/2 If this is a line equation then: (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, x/3 +3/2).

Travel_Word_Problems/176905: First thank you all. I have a word problem: Two steamers leave a port on a river at the same time, traveling in opposite directions. Each is traveling 22mph. How long will it take for them to be 110 mi. apart? 1 solutions Answer 132023 by checkley75(3666)   on 2009-01-15 21:55:58 (Show Source): You can put this solution on YOUR website! 22t+22t=110 44t=110 t=110/44 t=2.5 hours they'll be 110 miles apart.

Linear-equations/176932: Find the slope of each of the following lines. 1. y = -5x -17 2. 10 = y + x 3. y = 2x - 5 4. 4x + y = 0 5. 3x - 4y + 16 6. -2y - 16 + x 7. y = -11x - 3 8. y = -3x - 14 9. 2y + 2x = 18 10. 6x + 5y = 10 1 solutions Answer 132021 by checkley75(3666)   on 2009-01-15 21:53:24 (Show Source): You can put this solution on YOUR website! Y=mX+b is the line equation. m=slope 1. y = -5x -17 slope=-5 2. 10 = y + x y=-x+10 slope=-1 3. y = 2x - 5 slope=2 4. 4x + y = 0 y=-4x slope=-4 5. 3x - 4y + 16 where's the = sign? 6. -2y - 16 + x where's the = sign? 7. y = -11x - 3 slope=-11 8. y = -3x - 14 slope=-3 9. 2y + 2x = 18 2y=-2x+18 slope=-2 10. 6x + 5y = 10 5y=-6x+10 slope=-6

absolute-value/176947: This question is from textbook Simplify: (6x-2)+(2x+4) 1 solutions Answer 132018 by checkley75(3666)   on 2009-01-15 21:44:40 (Show Source): You can put this solution on YOUR website! (6x-2)+(2x+4) 6x+2x-2+4 8x+2 4(2x+1) ans.

Equations/176968: What is the slope of the line that passes through the points (3,2) and (1,7)? please help thanks! 1 solutions Answer 132016 by checkley75(3666)   on 2009-01-15 21:42:34 (Show Source): You can put this solution on YOUR website! slope=(y2-y1)/(x2-x1) slope=(7-2)/(1-3) slope=5/-2 slope=-2.5 ans.

Equations/176970: This question is from textbook pre-algebra NUMBER THEORY: Four times the sum of 3 consecutive intergers is 48. A. Write an equation that could be used to find the intergers B. What are the intergers. 1 solutions Answer 132015 by checkley75(3666)   on 2009-01-15 21:40:18 (Show Source): You can put this solution on YOUR website! 4(x+x+1+x+2)=48 4(3x+3)=48 12x+12=48 12x=48-12 12x=36 x=36/12 x=3 is the first integer 3+1=4 for the second 3+2=5 for the third Proof: 4(3+4+12=48 4*12=48 48=48

Linear_Equations_And_Systems_Word_Problems/176748: Find two numbers whose sum is 64 and whose difference is 4 . (We will call the two numbers x and y .) I am trying to help my son with some school work but I am not having much luck can yo help? 1 solutions Answer 131821 by checkley75(3666)   on 2009-01-14 20:53:50 (Show Source): You can put this solution on YOUR website! X+Y=64 X-Y=4 OR X=4+Y NOW REPLACE X WITH(4+Y) IN THE FIRST EQUATION (4+Y)+Y=64 4+2Y=64 2Y=64-4 2Y=60 Y=60/2 Y=30 ANS. X-30=4 X=30=4 X=34 ANS.

Bodies-in-space/176753: how do you find the slant hight of a cone with the altitiude of 12 and radias of 9?? 1 solutions Answer 131820 by checkley75(3666)   on 2009-01-14 20:50:10 (Show Source): You can put this solution on YOUR website! 9^2+12^2=S^2 81+144=S^2 225=S^2 S=SQRT225 S=15 ANS. FOR THE SLANT HEIGHT.

Divisibility_and_Prime_Numbers/176560: 6 2/9 divided by 5 1/9 - 7/8 equals what? 1 solutions Answer 131819 by checkley75(3666)   on 2009-01-14 20:46:36 (Show Source): You can put this solution on YOUR website! (6 2/9)/(5 1/9)-7/8 56/9*9/46-7/8 56/46-7/8 29/23-7/8=71/184 ANS. IF YOU MEAN: (6 2/9)/(5 1/9-7/8) THEN: (56/9)/(46/9-7/8) (56/9)/(305/72) 56/9*72/305=56*8/305=448/305 ANS.

Quadratic_Equations/176595: Please help. Solve for the length and width. The length of a rectangle is twice the width. The area of the rectangle is 162yd^2. Find L and W. Thank you 1 solutions Answer 131817 by checkley75(3666)   on 2009-01-14 20:35:59 (Show Source): You can put this solution on YOUR website! L=2W LW=162 2W*W=162 2W^2=162 W^2=162/2 W^2=81 W=SQRT81 W=9 ANS. L=2*9=18 ANS. pROOF: 9*18=162 162=162

Inequalities/176664: The width of a rectangle is fixed at 23cm. What lengths will make the perimeter greater than 90cm? 1 solutions Answer 131816 by checkley75(3666)   on 2009-01-14 20:32:13 (Show Source): You can put this solution on YOUR website! 2*23+2x>90 46+2x>90 2x>90-46 2x>44 x>44/2 x>22 ans. for the length to make the perimeter > 90.

Linear-systems/176670: .66x-.75y=-8 .33x+.5y=17 How do you solve by substitution? Show work? 1 solutions Answer 131815 by checkley75(3666)   on 2009-01-14 20:28:56 (Show Source): You can put this solution on YOUR website! .66x-.75y=-8 .33x+.5y=17 First you need to represent eith the x or the y unknown in terms of the other unknown. .33x=17-.5y x=(17-.5y)/.33 Now replace x in the other equation with (17-5y)/.33 & solve for y. .66(17-.5y)/.33-.75y=-8 2(17-.5y)-.75y=-8 34-y-.75y=-8 -1.75y=-8-34 -1.75y=-42 y=-42/-1.75 y=24 ans. x=(17-.5*24)/.33 x=(17-12)/.33 x=5/.33 x=15.1515

Miscellaneous_Word_Problems/176698: This question is from textbook Use inductive reasoning to determine the next three numbers in the pattern: 3, 12, 26, 45,....... 1 solutions Answer 131811 by checkley75(3666)   on 2009-01-14 20:13:19 (Show Source): You can put this solution on YOUR website! 3--12--26--45---69---98---132 -9---14--19--24---29---34--- difference ---5----5---5---5----5------ difference

Money_Word_Problems/176718: Maggie makes a $9.25 purchase at a bookstore in Reno with a $20 bill. The store has no bills and gives her the change in quarters and fifty-cent pieces. There are 30 coins in all. How many of each kind are there? please help thank you!! 1 solutions Answer 131809 by checkley75(3666)   on 2009-01-14 20:07:09 (Show Source): You can put this solution on YOUR website! 20-9.25=10.75 is the amount of change. .25x+.5(30-x)=10.75 .25x+15-.5x=10.75 -.25x=10.75-15 -.25x=-4.25 x=4.25/-.25 x=17 number of quarters. 30-17=13 number of half dollares. Proof: .25*17+.50*13=10.75 4.25+6.50=10.75 10.75=10.75

Linear-equations/176723: Write the standard form of the equation of the line with slope -1 passing through the point (-4,-6). Please Explain. Thank You! 1 solutions Answer 131807 by checkley75(3666)   on 2009-01-14 20:04:02 (Show Source): You can put this solution on YOUR website! Line through (-4,-6) with slope (m)=-1 is: Y=mX+b -6=-1*-4+b -6=4+b b=-6-4 b=-10 Y=-X-10 (graph 300x200 pixels, x from -10 to 5, y from -10 to 10, -x -10).

Polynomials-and-rational-expressions/176728: factor 7) 2r³+8r²+6r 1 solutions Answer 131805 by checkley75(3666)   on 2009-01-14 19:59:39 (Show Source): You can put this solution on YOUR website! 2r³+8r²+6r 2r(r^2+4r+3) 2r(r+3)(r+1)

Linear_Equations_And_Systems_Word_Problems/176734: find two numbers whose sum is 55 and whose difference is 15 let the numbers be x and y thank you 1 solutions Answer 131800 by checkley75(3666)   on 2009-01-14 19:57:22 (Show Source): You can put this solution on YOUR website! x+y=55 x-y=15 or x=15+y (15+y)+y=55 15+2y=55 2y=55-15 2y=40 y=40/2 y=20 ans. x+20=55 x=55-20 x=35 ans.

Equations/176729: Maggie makes a $9.25 purchase at a bookstore in Reno with a $20 bill. The store has no bills and gives her the change in quarters and fifty-cent pieces. There are 30 coins in all. How many of each kind are there? please help me! thank you!! 1 solutions Answer 131799 by checkley75(3666)   on 2009-01-14 19:54:22 (Show Source): You can put this solution on YOUR website! 20-9.25=10.75 is the amount of change. .25x+.5(30-x)=10.75 .25x+15-.5x=10.75 -.25x=10.75-15 -.25x=-4.25 x=4.25/-.25 x=17 number of quarters. 30-17=13 number of half dollares. Proof: .25*17+.50*13=10.75 4.25+6.50=10.75 10.75=10.75

Linear-systems/176439: This question is from textbook Teaching Textbooks Irving has 10% as many quarters as nickels. If Irving has $5.25 in quarters and nickels, how many nickels does he have? I first tried to add .10(.25) and .05x (because I don't know how many nickels, but that does not make sense when I try to solve it. I guess I don't understand what "10% as many" means. Does he have 10% more quarters? or 10% out of 100% are quarters? Either way, I can't figure out even how to set this problem up! Thanks for your help! 1 solutions Answer 131558 by checkley75(3666)   on 2009-01-13 17:43:27 (Show Source): You can put this solution on YOUR website! .1x*.25+.05x=5.25 .025x+.05x=5.25 .075x=5.25 x=5.25/.075 x=70 number of nickels. .1*70=7 number of quarters. Proof: 7*.25+.05*70=5.25 1.75+3.50=5.25 5.25=5.25

Proportions/176125: why do proportions solve it that way? 767:452=n;342 1 solutions Answer 131555 by checkley75(3666)   on 2009-01-13 17:35:54 (Show Source): You can put this solution on YOUR website! 767:452=n;342 452n=342*767 452n=262,314 n=262,314/452 n=580.34 ans.

Linear-systems/176004: Flying against the jetstream, a jet travels 2920km in 4 hours. Flying with the jetstream, the same jet travels 7630km in 7 hours. What is the speed of the jet in still air, and what is the speed of the jetstream? 1 solutions Answer 131132 by checkley75(3666)   on 2009-01-11 13:59:24 (Show Source): You can put this solution on YOUR website! D=RT 2920=R*4 R=2920/4 R=730 KMH AGAINST THE JETSTREAM. 7630=5*7 R=7630/7 R=1090 KMH QITH THE JETSTREAM. (1090-730)/2=360/2=180 KMH IS THE SPEED OF THE JETSTREAM. Proof: 730+180=910 speed of the jet in still air 1090-180=910 ditto.

Problems-with-consecutive-odd-even-integers/176013: Find the greatest of 4 consecutive integers if the least integer decreased by twice the greatest integer is 14. 1 solutions Answer 131128 by checkley75(3666)   on 2009-01-11 13:53:37 (Show Source): You can put this solution on YOUR website! Let x, x+1, x+2 & x+3 be the 4 consecutive integers. x-2(x+3)=14 x-2x-6=14 -x=14+6 -x=20 x=-20 ans. Proof -20-2(-20+3)=14 -20-2*-17=14 -20+34=14 14=14

Mixture_Word_Problems/176010: This question is from textbook thomas is going to make an open top box by cutting equal squares from the four corners on an 11 inch by 14 inch sheet of cardboard and folding up the sides. if the area of the base is to be 80 sqare inches then what size should be cut from each corner? 1 solutions Answer 131126 by checkley75(3666)   on 2009-01-11 13:49:11 (Show Source): You can put this solution on YOUR website! (11-x)(14-x)=80 154-25x+x^2=80 x^2-25x+154-80=0 x^2-25x+74=0 Using the quadratic equation we get: x=(25+-sqrt[-25^2-4*1*74])/2 x=(25+-sqrt625-296])/2*1 x=(25+-sqrt329)/2 x=(25+-18.138)/2 x=6.86/2 x=3.43 ans. for the size of the cut-out on the corners. Proof: (11-3.43)(14-3.43)=80] 7.57*10.57=80 80~80

Linear-systems/176009: Solve the system by substitution. y=2x-3 y=x-2 1 solutions Answer 131118 by checkley75(3666)   on 2009-01-11 13:35:58 (Show Source): You can put this solution on YOUR website! y=2x-3 y=x-2 x-2=2x-3 x-2x=-3+2 -x=-1 x=1 ans. y=2*1-3 y=2-3 y=-1 ans. Proof: -1=1-2 -1=-1

Linear-systems/176008: Solve the system by substitution. y=2x+4 y=-1/2x+3/2 1 solutions Answer 131116 by checkley75(3666)   on 2009-01-11 13:33:35 (Show Source): You can put this solution on YOUR website! y=2x+4 y=-1/2x+3/2 2x+4=-1/2x+3/2 2x+1/2x=3/2-4 2.5x=-2.5 x=-2.5/2.5 x=-1 ans. y=2*-1+4 y=-2+4 y=2 ans. Proof: 2=-1/2*-1+3/2 2=+1/2+3/2 2=4/2 2=2