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Recent problems solved by 'checkley71'

checkley71 answered: 8399 problems
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Equations/121436: Of all possible quotients of the numbers 10, -1/2, -5, and 1/5 which tow produce the largest quotient? Which two produce the smallest? 1 solutions Answer 89108 by checkley71(8403)   on 2008-01-20 20:52:00 (Show Source): You can put this solution on YOUR website! -1/2*-5=5/2=2.5 the largest quotient. 10*-5=-50 is the smallest quotient.

absolute-value/121432: These data represent the population of a certain city. Year Population (in thousands) 1950 18 1960 23 1970 29 1980 32 1990 38 2000 42 (a) Draw a line graph for the data. (b) Use the line graph to predict the population in the year 2010 1 solutions Answer 89106 by checkley71(8403)   on 2008-01-20 20:47:39 (Show Source): You can put this solution on YOUR website! Y=mX+b USING THE POINTS (5,18)(10,42) WE HAVE A SLOPE OF: (42-18)/(10-5)=24/5=4.8. NOW USING ONE SET OF POINTS WE FIND THE Y INERCEPT. 18=4.8*5+b b=18-24 b=-6 NOW WE HAVE THE LINE EQUATION: Y=4.8X-6 WHEN X=11 THE Y=4.8*11-6 OR Y=46.8 this says that the population in 2010 will be 46.8 thousand. (graph 300x300 pixels, x from -6 to 12, y from -10 to 50, y = 4.8x -6).

Quadratic_Equations/121352: Solve the equations for x. 25x squared = 13 2(x-5)squared = 3 1 solutions Answer 89105 by checkley71(8403)   on 2008-01-20 20:35:13 (Show Source): You can put this solution on YOUR website! 25X^2=13 X^2=13/25 X=SQRT13/25 X=.72 ANSWER. -------------------------------------- 2(X-5)^2=3 (X-5)^2=3/2 X-5=SQRT3/2 X=5+1.2247 X=1.2247-5 X=-3.7753 ANSWER.

Quadratic_Equations/121353: solve the equation for x by factoring the left-hand side. x squared + 4x + 4 = 7 1 solutions Answer 89104 by checkley71(8403)   on 2008-01-20 20:29:41 (Show Source): You can put this solution on YOUR website! X^2+4X+4=7 (X+2)^2=7 X+2=SQRT7 X+2=2.6575 X=2.6575-2 X=.6575 ANSWER.

Linear-equations/121434: x+6=2x+5 1 solutions Answer 89103 by checkley71(8403)   on 2008-01-20 20:27:06 (Show Source): You can put this solution on YOUR website! X+6=2X+5 X-2X=5-6 -X=-1 X=1 ANSWER. PROOF 1+6=2*1+5 7=7

Quadratic_Equations/121354: Solve by completeing the square. x squared - 6x -3 = 0 2x squared + 10x + 11 = 0 1 solutions Answer 89102 by checkley71(8403)   on 2008-01-20 20:25:34 (Show Source): You can put this solution on YOUR website! X^2-6X-3=0 X^2-6X+9=3+9 (X-3)^2=12 X-3=SQRT12 X=3+3.464 X=6.464 ANSWER. ---------------------------------- 2X^2+10X+11=0 2X^2+10X=11 2(X^2+5X+6.26)=11+2*6.25 2(X+5/2)^2=11+12.5 (X+5/2)^2=23.5/2 (X+5/2)^2=11.75 X+2.5=SQRT11.75 X=-2.5+3.4278 X=.92378 ANSWER.

Quadratic_Equations/121355: Solve. Find 2 consecutive positive integers such that the sum of their squares is 85. 1 solutions Answer 89101 by checkley71(8403)   on 2008-01-20 20:14:53 (Show Source): You can put this solution on YOUR website! X^2+(X+1)^2=85 X^2+X^2+2X+1=85 2X^2+2X+1-85=0 2X^2+2X-84=0 2(X^2+X-42)=0 2(X+7)(X-6)=0 X-6=0 X=6 ANSWER 6+1=7 ANSWER. PROOF 6^2+7^2=85 36+49=85 85=85

Signed-numbers/121357: This question is from textbook algebra for college students -3-(7)/3-5 is the question. i am haveing trouble with the positive and negative. when you add and subtract and when it becomes multiplacation 1 solutions Answer 89100 by checkley71(8403)   on 2008-01-20 20:00:03 (Show Source): You can put this solution on YOUR website! -3-(7)/3-5=-3-7/3-5=-8-7/3=(-24-7)/3=-31/3 ANSWER.

Graphs/121430: Find the slope of the line passing through the points (13, 13) and (1, 1). 1 solutions Answer 89099 by checkley71(8403)   on 2008-01-20 19:56:30 (Show Source): You can put this solution on YOUR website! SLOPE=(Y2-Y1)/(X2-X1)=(1-13)/(1-13)=-12/-12=1 FOR THE SLOPE.

Graphs/121431: Write the equation of the line that passes through point (0, 6) with a slope of -7/2 . 1 solutions Answer 89098 by checkley71(8403)   on 2008-01-20 19:53:35 (Show Source): You can put this solution on YOUR website! Y=mX+b 6=-7/2*0+b b=6 THUS THE EQUATION IS: Y=-7X/2+6 ANSWER.

Expressions-with-variables/121375: Find the solution to system of equations by substitution. Problem: Y=2X+7 and Y=-X-5. I am confused on which equation do i insert and when. For this problem I tried Y=-X(2X+7)-5, Then I'm stumped, I think the -x multiplied by the 2x is messing me up. Plus both of these start with Y=. The other examples problems show x+2y=6 and 4y=12-2x ? Totally different. Can you help me sort out how to do substition? How to start. I have went thru example after example in book and I keep getting the wrong answers I am missing a step or concept i think. 1 solutions Answer 89097 by checkley71(8403)   on 2008-01-20 19:51:20 (Show Source): You can put this solution on YOUR website! Y=2X+7 NOW REPLACE THE Y IN THE OTHER EQUATION WITH(2X+7) & SOLVE FOR X. 2X+7=-X-5 2X+X=-5-7 3X=-12 X=-12/3 X=-4 ANSWER. Y=2*-4+7 Y=-8+7 Y=-1 ANSWER. PROOF -1=-(-4)-5 -1=4-5 -1=-1 --------------------------------------------------- X+2Y=6 OR X=6-2Y NOW REPLACE X IN THE OTHER EQUATION WITH(6-2Y) & SOLVE FOR Y. 4Y=12-2(6-2Y) 4Y=12-12-2Y 4Y+2Y=0 2Y=0 Y=0 ANSWER. X+2*0=6 X=6 ANSWER. PROOF 4*0=12-2*6 0=12-12 0=0

Equations/121379: how do you remove brackets? e.g. 2(x+5) or a(a-4) multiply out of brackets and simplify? e.g. (x+3)(+2) or (2c-3)(3c+4) 1 solutions Answer 89096 by checkley71(8403)   on 2008-01-20 19:42:56 (Show Source): You can put this solution on YOUR website! 2(X+5)=2X+10 ANSWER. A(A-4)=A^2-4A ANSWER. (X+3)(+2)=2X+6 ANSWER. (2C-3)(3C+4)=6C^2-9C+8C-12=6C^2-C-12 ANSWER.

Linear-equations/121427: Find the slope of the line passing through the points (10, –4) and (–3, –6). 1 solutions Answer 89095 by checkley71(8403)   on 2008-01-20 19:38:25 (Show Source): You can put this solution on YOUR website! SLOPE=(Y2-Y1)/(X2-X1)=(-6+4)/(-3-10)=-2/-13=2/13 IS THE SLOPE.

Exponents-negative-and-fractional/121370: Please help me learn how simplify and solve: Fraction 7 over xto the neg 2 1 solutions Answer 89094 by checkley71(8403)   on 2008-01-20 19:26:51 (Show Source): You can put this solution on YOUR website! 7/X^-2=7X^2 ANSWER.

Linear-systems/121371: Find an equation of the line containing the given pair of points (-2, -9) and (-6, -7). Please show your steps. Thank you 1 solutions Answer 89093 by checkley71(8403)   on 2008-01-20 19:24:38 (Show Source): You can put this solution on YOUR website! FIRST WE FIND THE SLOPE (m) M=(Y2-Y1)/(X2-X1)=(-7+9)/(-6+2)=2/-4=-1/2 IS THE SLOPE NOW REPLACE THE X & Y TERMS IN THE LINE EQUATION[Y=mX+b] & SOLVE FOR b. -9=-1/2*-2+b -9=1+b b=-9-1 b=-10 THE Y INTERCEPT. THUS THE LINE EQUATION IS: Y=-X/2-10

Linear-equations/121424: Solve the system by addition x+y=1 x-y=3 1 solutions Answer 89092 by checkley71(8403)   on 2008-01-20 19:20:08 (Show Source): You can put this solution on YOUR website! X+Y=1 X-Y=3 NOW ADD -------------------- 2X=4 X=4/2 X=2 ANSWER. 2+Y=1 Y=1-2 Y=-1 ANSWER.

Linear-equations/121422: Solve the system by graphing x-y=5 x+y=3 1 solutions Answer 89091 by checkley71(8403)   on 2008-01-20 19:18:24 (Show Source): You can put this solution on YOUR website! x-y=5 or -y=-x+5 or y=x-5 (red line) x+y=3 or y=-x+3 (green line) (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions y = x -5 and y = -x +3). ANSWER(4,-1).

Miscellaneous_Word_Problems/121377: Mark wants to have a semester average of 85 in his math class. The three 6-week grades and the semester exam grade count equally in figuring the semester average in his school. The first six weeks Mark scored 92, the second six weeks he scored 75, and the third sixweeks Mark scored 83. What does Mark score on the semester exam to have exactly an 85 average for the semester? It is a multiple choice question, but instead of going through all of the answers and wasting time, I would rather if you could explain to me how to do this problem faster[if there is one]. 1 solutions Answer 89090 by checkley71(8403)   on 2008-01-20 19:14:01 (Show Source): You can put this solution on YOUR website! (92+75+83+x)/4=85 (250+x)/4=85 now cross multiply. 250+x=4*85 250+x=340 x=340-250 x=90 is the score required for the last test. proof (92+75+83+90)/4=85 340/4=85 85=85

Permutations/121408: a certain car averages 28 miles per gallon. gasoline cost 1.11 per gallon. to the number of miles the car would be expected to go on 250 worth of gasoline? 1 solutions Answer 89089 by checkley71(8403)   on 2008-01-20 19:04:58 (Show Source): You can put this solution on YOUR website! 250/28*1.11=$9.91 for enough gas to drive 250 miles.

Numeric_Fractions/121414: Please help me solve the following question: In the problem 4/n plus 5/m, if m is the Lowest Common Denominator for the problem, what do you know about the relationship between n and m? Thank you so much, Brigid 1 solutions Answer 89088 by checkley71(8403)   on 2008-01-20 19:01:08 (Show Source): You can put this solution on YOUR website! WHAT YOU KNOW IS THAT N IS A FACTOR OF M.

Equations/121416: I need help with this problem so that I can help my daughter understand her homework. The problem is : 8x + 4y = 12 1 solutions Answer 89087 by checkley71(8403)   on 2008-01-20 18:58:42 (Show Source): You can put this solution on YOUR website! Thank you very much for your help. One more question... if the problem had been a minus ((8x-4y=12)) would it still be an addition on the right of the equal sign... or would the sign have changed? if you change all the signs by a negative sign you get the same equation. -(8x+4y=12) or -8x-4y=-12 or -4y=8x-12 or y=8x-4-12/-4 or y=-2x+3 --------------------------------------------------------------------- IF THIS IS A LINE EQUATION THEN: 8X+4Y=12 4Y=-8X+12 Y=-8X/4+12/4 Y=-2X+3 THIS LINE HAS A SLOPE=-2 & A Y INTERCEPT=3 (0,3). GRAPH FOLLOWS. (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, y = -2x +3).

Functions/121415: r-5 (times the square root of r) - 36 = 0 1 solutions Answer 89085 by checkley71(8403)   on 2008-01-20 18:55:17 (Show Source): You can put this solution on YOUR website! R-5SQRT*R-36=0 (SQRT*R-9)(SQRT*R+4)=0 ANSWER.

Proportions/121348: A man who is 75 inches tall is 15 inches on a TV monitor. The image of his friend is 13 inches tall on monitor. How tall is his friend. 1 solutions Answer 89084 by checkley71(8403)   on 2008-01-20 18:51:49 (Show Source): You can put this solution on YOUR website! 15/75=13/X 15X=13*75 15X=975 X=975/15 X=65 INCHS TALL IS THE ANSWER.

Average/121409: Write the equation of the line which has y-intercept (0, 5) and is perpendicular to the line with equation y = –3x + 1. 1 solutions Answer 89083 by checkley71(8403)   on 2008-01-20 18:43:32 (Show Source): You can put this solution on YOUR website! Y=-3X+1 THIS LINE HAS A SLOPE OF -3. A PERPENDICULAR LINE HAS SLOPE IS 1/3. IF THIS LINE PASSES (0,5) HAS A LINE EQUATION OF 5=1/3*+b b=5-1/3 b=(15-1)/3 b=14/3 Y=X/3+14/3 ANSWER.

Exponents/121376: This question is from textbook pre-algebra i really need help on my math i have an F on my math so ill give my first answer! 8 to the power of 13 over 8 to the power of 10 1 solutions Answer 89081 by checkley71(8403)   on 2008-01-20 18:35:07 (Show Source): You can put this solution on YOUR website! 8^13/8^10=8^3=512 ANSWER.

Polynomials-and-rational-expressions/121402: 5y2+6y+1 1 solutions Answer 89079 by checkley71(8403)   on 2008-01-20 18:25:08 (Show Source): You can put this solution on YOUR website! 5Y^2+6Y+1 (5Y+1)(Y+1) ANSWER.

Linear-equations/121405: please help me solve the following: -5(x+2)+3=5 1 solutions Answer 89078 by checkley71(8403)   on 2008-01-20 18:23:55 (Show Source): You can put this solution on YOUR website! -5(X+2)+3=5 -5X-10+3=5 -5X=5+10-3 -5X=12 X=12/-5 X=-12/5 OR -2.4 ANSWER. PROOF -5(-2.4+2)+3=5 -5*-.4+3=5 2+3=5 5=5

Polynomials-and-rational-expressions/121403: 18+7y-y2 1 solutions Answer 89077 by checkley71(8403)   on 2008-01-20 18:20:53 (Show Source): You can put this solution on YOUR website! checkley i think you copied the question wrong....the question was 18+7y-y^2....pls help thanks again ----------------------------------------------------- SORRY ABOUT THAT MISTAKE. SOLUTION FOLLOWS: 18+7Y-Y^2 Y^2-7Y-18 (y-9)(y+2)=0 y-9=0 y=9 y+2=0 y=-2

real-numbers/121401: Calculate the first 10 powers of i. Observe the pattern. Explain how to quickly calculate any whole number power of i.( ex. What is i^312?) I know how to calculate the first ten powers and I see the pattern but I am awful at explaining to other people. Can you help? 1 solutions Answer 89075 by checkley71(8403)   on 2008-01-20 18:11:17 (Show Source): You can put this solution on YOUR website! i^1=sqrt-1 i^2=-1 i^3=1sqrt-1 i^4=1 i^5=1sqrt-1 i^6=-1 i^7=-1sqrt-1 i^8=1 i^9=1sqrt-1 i^10=-1 --------------------------------------- i^312=i^(78*4) or i^4=1 IF THE POWER IS DIVISABLE BY 4 THEN THE ANSWER IS (1) IF DIVIDING THE POWER BY 4 GIVES A REMAINDER OF 1 THEN THE ANSWER IS (SQRT-1) IF DIVIDING THE POWER BY 4 GIVES A REMAINDER OF 2 THEN THE ANSWER IS (-1) IF DIVIDING THE POWER BY 4 GIVES A REMAINDER OF 3 THEN THE ANSWER IS (1SQRT-1)

Rate-of-work-word-problems/121396: This question is from textbook algebra and trigonometry with analiytic geometry A consulting engineer's time is billed at $100 per hour, and her assistant's is billed at $20 per hour. A customer received a bill for $1200 for a certain job. If the assistant worked 3 hours less than the engineer, how much time did each bill on the job? 1 solutions Answer 89072 by checkley71(8403)   on 2008-01-20 17:57:36 (Show Source): You can put this solution on YOUR website! 100X+20(X-3)=1200 100X+20X-60=1200 120X=1200+60 120X=1260 X=1260/120 X=10.5 HOURS WAS BILLED FOR THE ENGINEER OR: 100*10.5=$1050 WAS THE ENGINEER'S BILL. 20(10.5-3)=20*7.5=$150 WAS THE ASSISTANT'S BILL. PROOF 100*10.5+20*7.5=1200 1050+150=1200 1200=1200

Travel_Word_Problems/121398: a plane took 1 hour longer to travel 560 miles on the first portion of a flight than it took to fly 480 miles on the second portion. If the speed was the same for each portion, what was the flying time for second part of the trip? 1 solutions Answer 89070 by checkley71(8403)   on 2008-01-20 17:52:01 (Show Source): You can put this solution on YOUR website! 560/(X+1)=480/X 560X=480(X+1) 560X=480X+480 560X-480X=480 80X=480 X=480/80 X=6 HOURS FOR THE SECOND 480 MILE TRIP. 6+1=7 HOURS FOR THE FIRST 560 MILE TRIP. PROOF 560/7=480/6 80=80