Search results

  1. A

    this stumps me:

    I came across this problem at the end of one section of the algebra review in my precalculus. I will post the problem and how I tried to work it out--it has been asked of us to simplify the expression: Problem: Here is how I tried to simplify this: Here is what I got from my calculator: I...
  2. A

    why are there imaginary solutions to equation "x^4 = 256"?

    Problem: . . . . .49 x^4\, =\, 256 What I did: . . . . .x^4\, =\, 256 . . . . .x\, =\, \pm \sqrt[4]{256\,} . . . . .x\, =\, \pm 4 \qquad \mbox{(my solution)} . . . . .x\, =\, \pm 4,\, \pm 4i \qquad \mbox{(book's solution)} What i want to know is: Where did they get that plus/munus 4i? I...
  3. A

    what does this notation mean? "Verify (bar over)(z + w) = (bar over)(z) + (bar over)(w)" What are the bars?

    I came across this today in some problems at the end of a section and can find no reference to it in the text: What I don't understand is the symbols over the z+w and over the z and the w. What are they asking for here? Here is the solution the book gives but I can't figure out where they got...
  4. A

    what's happening here? (printed area v. blue margins: my answer works, book's answer doesn't)

    132. A square page in a book measures 10 inches on each side. The printed matter on the page is to be surrounded by a blue margin of uniform width on all sides. The area of the blue margin is to be equal to the area of the portion of the page containing the printed matter. What are the...
  5. A

    I can't think of any other way on this

    Here is the problem: I tried to solve this by adding the areas of those parts of the figure that seemed to contain whole squares: The sign before the 12 is supposed to be the sign for "approximates". I suppose in calculus there are ways of working with this kind of problem but I have no...
  6. A

    why is #A wrong?

    Here is the multiple choice problem: I chose A as being correct but worked out the others to be sure and found that B is the correct one or at least seems to have a little more claim to that status in that when I checked A on my calculator it said True for 7i but false when I tried -7i...
  7. A

    there seems to be to little info here, no?

    I broke my head butting it against this problem for over an hour today. I kept coming back to the conclusion that there was just too little information given. Here is the problem: Here is some documentary evidence of a miserable failure to solve it: Here is the solution as presented in the...
  8. A

    does this look promising

    Here is the problem: Here is how I am trying to set it up: I am aware that this is not exactly the way to go--I have already tried it. But is it in the ballpark at all? Obviously I am treating this as a hypotenuse situation. For one thing, the problem that came before was solved...
  9. A

    How to set up problems like this one?

    I know that -b/a is the sum of quadratic solutions and c/a is the product of solutions and I wonder if that is the key to solving this problem. Other than that I HAVE NO IDEA how to even begin. The solution, according to my instructions, must be arrived at by the quadratic formula. Here is the...
  10. A

    what goes on here?

    I tried to solve the following problem in two ways: Problem: I tried both the square root property solution and the quadratic formula: solutions: I then checked the answers with a CAS calculator. The calculator came back with the same solutions as the quadratic formula did. Now my question...
  11. A

    what is happening here?

    This seems to be a very simple equation...but somehow the solution is eluding me. I have tried again and again and can't get it to come out right. lIt is easy to see what the answer should be without working it out. But when I try to work it out, Mr Right doesn't show up. Equation: Correct...
  12. A

    what is wrong here?

    Here is problem: Here is how I solved it: Here is the solution in back of the book: Now, how can this be? I mean, all you need to do is eyeball the formula and know that that x is going to be 12 to know that you are going to get a number larger than 360. So, what am I missing. I tried...
  13. A

    is this an instance of a some arithmoalgeraic (?) rule

    Working out some problems today I came across an equivalence that surprised me. I am sorry I don't have a photo of this and neither do I have access to the tools I need to set it down symbolically. But it is easy to describe. I found that when I had a square root as a numeratorrand a number as a...
  14. A

    what's wrong here? I get "no real roots" for sqrt{2z} - sqrt{z + 7} = -1

    Here is the equation to be solved for x--it is actually z but I use x in my handwritten working out (attached) to avoid confusion of z with 2: \mbox{41.}\qquad \sqrt{\strut 2z\,}\, -\, \sqrt{\strut z\, +\, 7\,}\, =\, -1 Here is what I did--and this is only one version because I turned this...
  15. A

    a puzzle: I get 7/(sqrt{2}-7) equalling (-7 sqrt{2} + 49)/47, but calc says "no" ??

    a puzzle: I get 7/(sqrt{2}-7) equalling (-7 sqrt{2} + 49)/47, but calc says "no" ?? What is happening here? 90.. . .Is the following true? . . . . .A.. .\dfrac{7}{\sqrt{2\,}\, -\, 7}\, \mbox{ and }\, \dfrac{-7\, \sqrt{2\,}\, +\, 49}{47} have the same . . . . . . .decimal approximations when...
  16. A

    calculator question: Which is the best calculator for studying algebra?

    What is the best calculator for algebra? I want to use it more to check my work than to have it do the work for me. I am not as lazy as Lucy but neither am i as gifted as Bird:
  17. A

    how to simplify this radical fraction: 4th-root[ 225 / 81 ]

    This is not, strictly speaking, an algebra problem, but it was included in the problems given at the end of a section in my algebra book. I am being asked to simplify.Here is problem or expression or whatever it is: Here is book solution: Here is what I did: I know how to reduce this sort...
  18. A

    recommendations?

    I have been going through Robert Blixer's Introductory Algebra for College Students for the last year or so and am coming to the end of it. I wonder what would be a good book to use to continue studying this subject. Algebra to me is a kind of hobby. I like it better than playing video games or...
  19. A

    what's going on here?

    Here is the problem: Here is my solution and my solution checking: I tried this problem various times and always got the same answer. But...shouldn't multiplying the result of the division by 2 come out to 300$? I mean, 264$ isn't even respectably close.
  20. A

    two questions about: Let x,y,z be distinct, non-zero, one-digit numbers.

    This simple problem is from a series of review problems: Here is the book's solution: Here is what I did: Question 1) Where did the author get the 4? The two largest numbers are 5 and 7 and the difference can only be 2 or -2. Question 2) Is there a way to solve this problem using algebra...
Top