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anonymous

  • one year ago

need help with -7x<28 solve graph

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  1. phi
    • one year ago
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    this is tricky. because you have a < sign, we have to be careful if we multiply or divide by negative numbers. here, divide both sides by -7 and *switch the sign* to > you get x> -4

  2. anonymous
    • one year ago
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    it is tricky. I have a number line to put the answer on. also why did you make x>than -4

  3. phi
    • one year ago
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    here is an example with numbers -7 < -4 that says minus 7 is smaller than minus 4 (and it is) if we multiply (or divide by a negative number) , the sign must change. for example, say we multiply by -1 (on both sides), like this -1*-7 < -1*-4 7 < 4 and that is not true. but 7>4 is true.

  4. phi
    • one year ago
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    one way to stay out of trouble is only multiply by positive numbers. and use add/subtract for example -7x< 28 add 7x to both sides -7x+7x < 28 + 7x 0 < 28 + 7x now add -28 to both sides. we get -28 < 7x finally , divide both sides by 7 -28/7 < x -4 < x

  5. phi
    • one year ago
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    -4 < x the "big side of <" is next to x and the small end of < is next to -4 that means this says -4 is smaller than x or x is bigger than -4 we can also write it x> -4 which also means x is bigger than -4

  6. phi
    • one year ago
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    to graph it, make a number line. put an open circle O at -4 (if it were \( x \ge -4\) we would use a filled in circle) then show all the numbers bigger than -4 by drawing a line with an arrow head pointing toward the bigger numbers i..e toward 0

  7. anonymous
    • one year ago
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    I see. Thanks

  8. anonymous
    • one year ago
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    how about 1/3 >_ 2

  9. anonymous
    • one year ago
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