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  • Feb 9, 2011, 08:44 AM
    suzisu
    maths
    We are doing some sponsored challenges. We are sponsored for each correct answer. All money goes to children's charity work. We're at a loss with the maths! I'm doing a home tuition course, but I still don't understand a lot of areas.
    It doesn't matter how many are in a group or who helps you. We have answered over half the questions but are stuck on some of them, others we are not sure about the answers we have come up with. Would appreciate help to any of the questions below. Thanks.

    1.
    Solve the equation, give your answer as a fraction in its lowest terms:
    2x – 5=7-6x

    We got -1/3 but that seems wrong!?


    2.
    Solve the equation, give your answer as a fraction in its lowest terms:
    x-2= 4x+7/6 (the whole part 4x+7 is over the 6)

    Some of us got 3 and others got 1/6, so we need help!

    3.
    Y is directly proportional to x
    If y= 10 when x=-5 what is the value of y when x =30. The answer should be a number.

    4.
    This question is about plotting two points and drawing the straight line through them. Which two options are correct instructions for plotting two points which can then be used to draw the line y=2x+5. Select one or more.
    A) Plot the points (1.3) and (2,-1)
    b) Plot the points (1.3) and (1, 7)
    c) Plot the point (-2, 0) trace 1 unit horizontally to the right of this and plot the second point. D) Plot the point (5, 0). Trace 1 unit horizontally to the right of this and 2 units down and plot the second point.
    E) Plot the point (0.5) Trace 2 units horizontally to the right of this and 4 units down and plot the second point.
    F) Plot the points (1, 2) and (2, 1)

    5.
    Select the option that is the equation
    y=2x-2
    rearranged to make x the subject of the equation.
    Select one:
    x=y+1 or x=-y/2+1 or x=-y+1
    or x=-y/2-2 or x=y/2=1
    or x=y-2 or x=-y-2

  • Feb 9, 2011, 09:47 AM
    Unknown008

    Quote:

    1.
    Solve the equation, give your answer as a fraction in its lowest terms:
    2x – 5=7-6x

    We got -1/3 but that seems wrong!?
    You have another thread on that. We'll keep that there.

    Quote:

    2.
    Solve the equation, give your answer as a fraction in its lowest terms:
    x-2= 4x+7/6 (the whole part 4x+7 is over the 6)

    Some of us got 3 and others got 1/6, so we need help!
    To check your answers, just plug them in the equation back.





    Obviously, this is wrong.





    Here again, this is wrong...

    I also considered the case where the equation is:



    But none of the answers fit. Before going on, is that the correct equation? Make us of brackets to avoid confusion.

    Quote:

    3.
    Y is directly proportional to x
    If y= 10 when x=-5 what is the value of y when x =30. The answer should be a number.
    Yes,



    So,



    Find k when y = 10 and x = -5. Then, find y having k and x = -5.

    Or a shortcut,



    So,

    Quote:

    4.
    This question is about plotting two points and drawing the straight line through them. Which two options are correct instructions for plotting two points which can then be used to draw the line y=2x+5. Select one or more.
    A) Plot the points (1.3) and (2,-1)
    b) Plot the points (1.3) and (1, 7)
    c) Plot the point (-2, 0) trace 1 unit horizontally to the right of this and plot the second point. D) Plot the point (5, 0). Trace 1 unit horizontally to the right of this and 2 units down and plot the second point.
    E) Plot the point (0.5) Trace 2 units horizontally to the right of this and 4 units down and plot the second point.
    F) Plot the points (1, 2) and (2, 1)
    Did you mean (1, 3) and (2, -1) ?

    Anyway, you have to ensure that the points selected are on the line. That is, putting x = 1 and y = 3, the equation should be satisfied. Same goes for the other points.

    Keep in mind the gradient, that is 2. The points should not be on a horizontal line, or a vertical line, but a line pointing about in a North East direction.

    Quote:

    5.
    Select the option that is the equation
    y=2x-2
    rearranged to make x the subject of the equation.
    Select one:
    x=y+1 or x=-y/2+1 or x=-y+1
    or x=-y/2-2 or x=y/2=1
    or x=y-2 or x=-y-2

    1. Add 2
    2. Divide by 2.

    What do you get?
  • Feb 9, 2011, 09:57 AM
    suzisu
    Thanks:

    For question 2: I tried adding 6x to both sides and adding 5 to both sides.
    so 8x=12
    divide by 8=3/2 but my friend says its 3/1 !

    Question 4 doesn't make a lot of sense to me. I've tried plotting the points, but it just keeps getting me frustrated! Sorry!

    For question 5 I think x=y/2-2 is correct?
  • Feb 9, 2011, 11:25 AM
    Unknown008

    2. I'm still aren't sure what's the question!! :confused:

    Is it: or ?

    3. Anything you tried?

    4. Okay.

    Let's consider A. Points (1, 3) and (2, -1) make a gradient of -4, but in the question, the gradient is 2, so it's wrong.

    B now. You immediately see that both points share the same point, so no.

    C. Since you only moved horizontally from the first point, the gradient is 0, again no.

    D. From (5, 0), 1 unit right and 2 units down give the point (6, -2), giving a gradient of -2, still not good.

    E. (0, 5), 2 units right and 4 units down give the point (2, 1), giving a gradient of -2, which is still not good.

    F must be the good one. Let's see. (1, 2) and (2, 1) give a gradient of -1.

    Hm... you have made a mistake in typing the question. I'd guess the equation is in fact y = -2x + 5. Which means, we are looking for a gradient of -2 instead. Immediately, you see that D and E have gradients -2. So, not, test in a point from D and one point from E.

    D: (5, 0), putting in the equation immediately gives you: (0) = -2(5) + 5 which is false since it becomes 0 = -5

    E: (0, 5) Since it's the last choice, that must be it. But let's confirm. (5) = -2(0) + 5 giving 5 = 5 which is true! E is therefore the answer.

    5.

    No



    adding 2:



    Can you try it again?

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