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# Recent problems solved by 'richwmiller'

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 Volume/631983: the water in a cylinder,A,of radius 24 cm is poured into another cylinder,B, of radius 36cm. Find the height of water in cylinder B. 1 solutions Answer 397942 by richwmiller(9143)   on 2012-07-25 22:25:36 (Show Source): You can put this solution on YOUR website!How deep is the water in cylinder a?
 Polynomials-and-rational-expressions/631966: i need help finding the solution to the equation below, (x-5)^2=71 solutions Answer 397929 by richwmiller(9143)   on 2012-07-25 20:50:47 (Show Source): You can put this solution on YOUR website!(x-5)^2=7 x-5=+-sqrt(7) x=5+sqrt(7) x=5-sqrt(7)
 Linear_Equations_And_Systems_Word_Problems/631951: If the sum of 8 and a number is multiplied by 5 the result is 45 what is the number?...... I know the number is 1 but how do u get that number?1 solutions Answer 397928 by richwmiller(9143)   on 2012-07-25 20:36:59 (Show Source): You can put this solution on YOUR website!(8+x)*5=45 40+5x=45 5x=5 x=1
 Geometric_formulas/631961: If EF is perpendicular to planes P and R, which statement must be true? 1) Plane P is perpendicular to plane Q. 2) Plane R is perpendicular to plane P. 3) Plane P is parallell to plane Q. 4) Plane R is parallell to plane P.1 solutions Answer 397924 by richwmiller(9143)   on 2012-07-25 20:26:17 (Show Source): You can put this solution on YOUR website!4) parallel r and p
 Permutations/631932: A pizza place offers 3 different cheeses and 8 different toppings. In how many ways can a pizza bemade with 1 cheese and 3 toppings?1 solutions Answer 397909 by richwmiller(9143)   on 2012-07-25 18:58:16 (Show Source): You can put this solution on YOUR website!3*8*7*6 if you don't double any of the toppings
 Linear-equations/631934: what is the solution for the equation x+1=x+2 ?1 solutions Answer 397908 by richwmiller(9143)   on 2012-07-25 18:52:01 (Show Source): You can put this solution on YOUR website!There is no solution. Think about it. The equations say that if you have a certain quantity (x) that you get the same result if you add one to it or if you add 2 to it. Can you get the same total if I give you one dollar and if I give you two dollars?
 Money_Word_Problems/631935: working 2 part time jobs .how long would it take to reach 7000 dollars1 solutions Answer 397907 by richwmiller(9143)   on 2012-07-25 18:41:40 (Show Source): You can put this solution on YOUR website!two years
 Miscellaneous_Word_Problems/631889: it takes 8 hours to dig a hole. it would take you and another person 5 hours to dig that same hole together. if the other person were to dig himself it would take how many hours?1 solutions Answer 397868 by richwmiller(9143)   on 2012-07-25 15:50:09 (Show Source): You can put this solution on YOUR website!Hole digging is a one person job. Two people can't fit in the hole without getting in each other's way. 5/8+5/x=1 5/x=3/8 40=3x 40/3=x
 Square-cubic-other-roots/631888: Simplify : (√2-3)(√2+3) I got : -7-√2 Please show work through steps so I can understand this properly and know where I went wrong if I completed this incorrectly. Thank you for your time !! I realy appreciate it :) 1 solutions Answer 397864 by richwmiller(9143)   on 2012-07-25 15:38:45 (Show Source): You can put this solution on YOUR website!Where are your steps? Use foil first outer inner last or you should know that x^2-y^2=(x+y)*(x-y) where x=sqrt(2) and y=3 answer should be 2-9=-7
 Probability-and-statistics/631866: A bookcase is to have four shelves, including the top. The height of the bookcase is to be 2 feet more than the width and only 20 feet of lumber is available. Use an equation to determine the width and height of the bookcase.1 solutions Answer 397860 by richwmiller(9143)   on 2012-07-25 15:28:56 (Show Source): You can put this solution on YOUR website!4w+2h=20; h=w+2 4w+2(w+2)=20 4w+2w+4=20 6w=16 3w=8 w=8/3 h=8/3+6/3=14/3
 Square-cubic-other-roots/631863: Stumped on square root problem: Express in terms of i. -sqrt-496 My brain is totally frazzled on this. Thanks for helping me if you can!1 solutions Answer 397855 by richwmiller(9143)   on 2012-07-25 15:13:20 (Show Source): You can put this solution on YOUR website!Take a break and come back to your problems. You submitted too many frazzled problems today.
 Polynomials-and-rational-expressions/631865: Multiplty:show your steps please. (2x-4)(x^2-x-1) This is my last problem, and my brain is frazzled. Can you help? Thanks in advance. 1 solutions Answer 397853 by richwmiller(9143)   on 2012-07-25 15:11:15 (Show Source): You can put this solution on YOUR website!Take a break and come back to your problems. You submitted too many frazzled problems today.
 Linear_Equations_And_Systems_Word_Problems/631873: Need help!! Find out how many calls must be made to make Plan A the better deal. • Plan A: \$45 a month for unlimited calling • Plan B: \$15 a month plus \$0.10 per minute Complete the following steps to solve the above problem: a. Write the cost equation for Plan A: b. Write the cost equation for Plan B: c. Use the equations written in steps a) and b) to show the inequality that models the given conditions. Solve the inequality to find out how many calls must be made to make Plan A the better deal. 1 solutions Answer 397850 by richwmiller(9143)   on 2012-07-25 15:07:56 (Show Source): You can put this solution on YOUR website!plan a y=45 plan b y<.1m+15 45<.1m+15 30<.1m 300 after 300 minutes plan a is cheaper
 Length-and-distance/631870: Find the length of a ramp that is 8ft long and 6ft high1 solutions Answer 397848 by richwmiller(9143)   on 2012-07-25 15:00:08 (Show Source): You can put this solution on YOUR website!this is a double of a 3-4-5 right triangle so the ramp is 10 also 36+64=100 10^2=100
 test/631868: 1 solutions Answer 397846 by richwmiller(9143)   on 2012-07-25 14:55:53 (Show Source): You can put this solution on YOUR website!yes
 Mixture_Word_Problems/631789: A chemist needs 90 milliliters of a 42% solution but has only 38% and 47% solutions available. Find how many milliliters of each that should be mixed to get the desired solution.1 solutions Answer 397801 by richwmiller(9143)   on 2012-07-25 10:56:36 (Show Source): You can put this solution on YOUR website!x+y=90; .38x+.47y=.42*90 x=50 of the 38% y=40 of the 47%
 Linear_Equations_And_Systems_Word_Problems/631765: Jeff, Tom, and Chelsea order a large pizza. They decide to split the cost according to how much they will eat. Tom pays \$7.80, Chelsea eats 1/8 of the pizza, and Jeff eats 1/2 of the pizza. How much did the pizza cost?1 solutions Answer 397798 by richwmiller(9143)   on 2012-07-25 10:47:10 (Show Source): You can put this solution on YOUR website!1/8+1/2+t=1 1/8+4/8+t=1 5/8+t=1 t=3/8 3c/8=780 c=20.80
 Quadratic_Equations/631780: when the price of an orange is reduced by 50 paise, i find that by paying an extra Rs 3, i can buy 3 dozen instead of 2 and a half dozen. how much did an orange cost before the reduction in price?1 solutions Answer 397795 by richwmiller(9143)   on 2012-07-25 10:31:05 (Show Source): You can put this solution on YOUR website!36*(c-50)=30c+300 c=350
 Quadratic_Equations/631777: a man spends Rs 5 on bar chocolates. had they been 2 and a half paisa, he would have bought 10 more. how many did he buy?1 solutions Answer 397789 by richwmiller(9143)   on 2012-07-25 10:03:34 (Show Source): You can put this solution on YOUR website!Assuming they were Rs5 for each bar. n*5=2.5(n+10) He originally bought 10 bars at Rs5 each check 5*10=2.5*(10+10) 50=2.5*20 ok
 Geometry_Word_Problems/631572: The length to height ratio of a rectangular window is 5 inches to 4 inches. What is the height of this window if the length is 40 inches? 1 solutions Answer 397676 by richwmiller(9143)   on 2012-07-24 19:23:15 (Show Source): You can put this solution on YOUR website!40/5=8 4*8=32
 Linear-systems/631566: Use the method of substitution to solve the system of linear equations. 2x-y=4 9x-4y=21 The solution is ______. Please show work! Thank you This what I have tried thus far: 2x-y=4 y=2x-4 9x-4y=21 9x-4(2x-4)=21 1 solutions Answer 397673 by richwmiller(9143)   on 2012-07-24 19:15:44 (Show Source): You can put this solution on YOUR website!So keep going.
 Linear-equations/631514: 1. Find an equation of the line that contains the given pair of points. Write the equation in the form y=mx+b. (9,7) (9,-10). 2. Find the slope and thr y-intercept of the line. y=6 3. Determine whether the graphs are parrallel, perpendicular lines or neither. x=-2 and x=81 solutions Answer 397669 by richwmiller(9143)   on 2012-07-24 18:51:53 (Show Source): You can put this solution on YOUR website!Too many questions. One question per submission and no similar questions. Ill answer 2 and 3 2- slope is 0. y never changes. y intercept is when x=0 (0,6) horizontal line 3) parallel slope is undefined since x( the denominator) never changes and the change in x is 0. Division by zero is undefined. Vertical line
Polynomials-and-rational-expressions/631560: how do i factor 8x^2-24x+18? i'm quite confused and can't seem to find a solution!
1 solutions

Answer 397665 by richwmiller(9143)   on 2012-07-24 18:34:21 (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Factoring using the AC method (Factor by Grouping)
In order to factor , first multiply the leading coefficient 8 and the last term 18 to get 144. Now we need to ask ourselves: What two numbers multiply to 144 and add to -24? Lets find out by listing all of the possible factors of 144

Factors:

1,2,3,4,6,8,9,12,16,18,24,36,48,72,144,

-1,-2,-3,-4,-6,-8,-9,-12,-16,-18,-24,-36,-48,-72,-144, List the negative factors as well. This will allow us to find all possible combinations

These factors pair up to multiply to 144.

1*144=144

2*72=144

3*48=144

4*36=144

6*24=144

8*18=144

9*16=144

12*12=144

(-1)*(-144)=144

(-2)*(-72)=144

(-3)*(-48)=144

(-4)*(-36)=144

(-6)*(-24)=144

(-8)*(-18)=144

(-9)*(-16)=144

(-12)*(-12)=144

note: remember two negative numbers multiplied together make a positive number

Now which of these pairs add to -24? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to -24

||||||||||||||||
 First Number | Second Number | Sum 1 | 144 | 1+144=145 2 | 72 | 2+72=74 3 | 48 | 3+48=51 4 | 36 | 4+36=40 6 | 24 | 6+24=30 8 | 18 | 8+18=26 9 | 16 | 9+16=25 12 | 12 | 12+12=24 -1 | -144 | -1+(-144)=-145 -2 | -72 | -2+(-72)=-74 -3 | -48 | -3+(-48)=-51 -4 | -36 | -4+(-36)=-40 -6 | -24 | -6+(-24)=-30 -8 | -18 | -8+(-18)=-26 -9 | -16 | -9+(-16)=-25 -12 | -12 | -12+(-12)=-24

We can see from the table that -12 and -12 add to -24. So the two numbers that multiply to 144 and add to -24 are: -12 and -12

So the original quadratic

breaks down to this (just replace with the two numbers that multiply to 144 and add to -24, which are: -12 and -12)

Replace with

Group the first two terms together and the last two terms together like this:

Factor a 4x out of the first group and factor a -6 out of the second group.

Now since we have a common term we can combine the two terms.

Combine like terms.
==============================================================================

So the quadratic factors to

Notice how foils back to our original problem . This verifies our answer.

 Human-and-algebraic-language/631550: Kate got x amount of dollars for a birthday gift, she spent \$10.00 on something then spent 30% of what was left over and saved the rest. What represents the amount Kate saved?1 solutions Answer 397664 by richwmiller(9143)   on 2012-07-24 18:20:35 (Show Source): You can put this solution on YOUR website!Katie spent 30 % and saved 70% saved=.70(x-10)
 Matrices-and-determiminant/631491: Use matrices to solve the system of equations (if possible). Use Gaussian elimination with back-substitution or Gauss-Jordan elimination. (If there is no solution, enter NO SOLUTION. If the system is dependent, set z = a and solve for x and y in terms of a.) 3x − 2y + z = 7 −x + y + 2z = −12 x − y − 4z = 20 (x,y,z)=1 solutions Answer 397618 by richwmiller(9143)   on 2012-07-24 15:09:05 (Show Source): You can put this solution on YOUR website!x = 3, y = -1, z = -4
 Miscellaneous_Word_Problems/631468: A businessman drives from Washington DC to Boston a distance of 442 miles and then makes the the return trip. On the way to Boston he drives 65 miles per hour taking a 1 hour rest stop during the drive. After finishing his business his business in Boston he makes the return trip driving at 60 miles per hour and takes a 45 min rest stop halfway through the trip. Which leg of the journey Washington to Boston or Boston to Washington DC takes the longer time?1 solutions Answer 397617 by richwmiller(9143)   on 2012-07-24 15:04:21 (Show Source): You can put this solution on YOUR website!to Boston x=442/65 +1 return trip to DC y=442/60+3/4 x~~7.8=468 minutes y~~8.11667= 487 minutes The return trip takes longer by about 19 minutes
 test/631359: What is the setting of The Screwtape Letters?1 solutions Answer 397528 by richwmiller(9143)   on 2012-07-24 10:19:49 (Show Source): You can put this solution on YOUR website!Hell and earth.
 Triangles/631368: Please help me solve this equation: Triangle ABC is isosceles with AC = BC. If AC = 3x + 8, BC = 5x - 4, and AB = 2x + 4, find the perimeter of the triangle. I have tried solving this by myself already by solving for x and then substituting it, but the answers I get are not equal. It says that AC and BC are supposed to be congruent, but my answers are very far from each other. However, I think I got the formula for this correctly. Since it isn't a regular polygon, the formula for the perimeter is the two sides + the base, right? Please correct me if I'm wrong. 1 solutions Answer 397525 by richwmiller(9143)   on 2012-07-24 10:12:24 (Show Source): You can put this solution on YOUR website!set the two sides equal 3x+8=5x-4 12=2x 6=x check 30-4=26 ok 18+6=24 ok The perimeter is the sum of the three sides. p=3x+8+5x-4+2x+4 p=24+24+16 p=64
 Equations/631318: Given 3x+k-5 = kx-k+1, what is the value of k to make x=0 be the solution of the linear equation?1 solutions Answer 397505 by richwmiller(9143)   on 2012-07-24 04:29:43 (Show Source): You can put this solution on YOUR website!plug in 0 for x and find k 3x+k-5 = kx-k+1 k-5=-k+1 2k=6 k=3 check plug in 3 for k and see if x=0 3x+3-5=3x-3+1 -2=-2 ok when k=3 x can equal anything.
 Money_Word_Problems/631237: A cell phone carrier charges \$15/month and \$0.40/minute. Another carrier charges \$30/month and \$0.25/minutes. How many minutes need to be used to make the plans equal?1 solutions Answer 397454 by richwmiller(9143)   on 2012-07-23 20:20:58 (Show Source): You can put this solution on YOUR website!y=.4x+15; y=.25x+30 100 minutes will cost \$55 dollars
 Miscellaneous_Word_Problems/631172: The problem is about what a family needs to pay for during a vacation and how long they can stay, I've figured everything out, but one of the expenses is the Daily Car Rental. For days over 7, it costs \$25. What does that mean? Daily Car Rental for days over 7 is \$25.1 solutions Answer 397453 by richwmiller(9143)   on 2012-07-23 20:15:25 (Show Source): You can put this solution on YOUR website!over 7 means after 7 days