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Math Help - quick simplifying question

  1. #1
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    quick simplifying question

    i have a quick question with simplifying a variable expression can someone tell me what one is correct? heres the problem 8-12x+20 is simplified to what A)28-12x or B)-12x+28?
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  2. #2
    MHF Contributor alexmahone's Avatar
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    Both the expressions A) and B) are equal.
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  3. #3
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    wow, yea im stupid i checked it in the calculator before i posted, but i must of put it in wrong bcuz now it comes out correct
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  4. #4
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    im not going to open up a new thread for this but can anyone figure this out?

    find three consecutive integers such that the sum of the first two is 18 more than the third
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  5. #5
    MHF Contributor alexmahone's Avatar
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    Let the 3 consecutive integers be a-1,\ a,\ a+1

    (a-1)+a=18+(a+1)

    2a-1=19+a

    a=20

    So the 3 integers are 19, 20 and 21.
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  6. #6
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    what about find the measure of the three angles of a triangle if the second angle is twice the first angle and the third angle is 20 more than the first angle?
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  7. #7
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    First angle = x
    Second angle = 2x
    Third angle = x + 20

    The sum of the three angles in a triangle is 180:
    x + 2x + x + 20 = 180

    Can you take it from here?


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  8. #8
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    yes i can take it from there, idk why u have such a hard time setting these up, 2 more if u dont mind

    a 31 inch pipe is cut into two pieces. three times the larger piece is equal to nine more than three times the smaller piece.find the lenth of the smaller peice

    ^that one i dont even know how to set up

    heres the last one
    if you reveived a 58 and a 78 on the first two math test, what grade would you need on the next test to have a 70 average

    ^now that one i got the answer to wich is 74 but i had to do it the long way because i have such a hard time trying to set up these problems
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  9. #9
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    Quote Originally Posted by wonderd View Post
    yes i can take it from there, idk why u have such a hard time setting these up, 2 more if u dont mind

    a 31 inch pipe is cut into two pieces. three times the larger piece is equal to nine more than three times the smaller piece.find the lenth of the smaller peice

    ^that one i dont even know how to set up
    Take the first part of the problem: "a 31 inch pipe is cut into two pieces." So there are two pieces with lengths x and y. Together their length must equal 31 inches. "Together" means addition, so
    x + y = 31
    is your first equation.

    Now take the second part of the problem: "three times the larger piece is equal to nine more than three times the smaller piece."
    Again, we have the lengths of the two pieces of pipe, x and y. It doesn't matter which is larger; let's say that x is. So
    "three times the larger piece..." means 3x,
    "is equal to..." means =,
    "nine more than three times the smaller piece." means 3y + 9.
    Therefore the 2nd equation is
    3x = 3y + 9.

    You have two equations and two unknowns.
    x + y = 31
    3x = 3y + 9
    Can you take it from there?

    heres the last one
    if you reveived a 58 and a 78 on the first two math test, what grade would you need on the next test to have a 70 average
    To find the average of a bunch of numbers, add the numbers up and divide by the number of numbers there are. How many test grades are there? Three: 58, 78, and an unknown number, which we'll call x. Find it's average:
    \frac{58 + 78 + x}{3} = 70
    That's the equation. Take it from there!


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  10. #10
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    You have two equations and two unknowns.


    Can you take it from there?

    i havent gotten that far in math yet, idk how to find two unknows, and its asking for one number not 2
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