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- 68
- êêïDIVIDING FRACTIONS, INTERMEDIATE LEVEL
-
- è In this section we will be looking at dividing positive and/or
- negative fractions.ïYou recall in the Elementary Level that when you
- divided two positive fractions, you always got a positive fraction
- as an answer.ïIn this section we are really considering dividing
- any fraction, positive or negative, by any other fraction, positive
- or negative.ïThere will be two rules to cover the different cases.
- The first rule is used when dividing two fractions that are both
- positive or both negative.ïThe second rule will be for dividing two
- fractions with different signs.ïThe following list shows the set of
- all fractions.
- êêêêïFractions
-
- #êë ... -╩ï-╔è╚è╔è╩è╦è╠è═è╬ ...
- êêè 1è1è1è1è1è1è1è1è1
-
- #êë ... -╩ï-╔è╚è╔è╩è╦è╠è═è╬ ...
- êêè 2è2è2è2è2è2è2è2è2
-
- #êë ... -╦ï-╔è╚è╔è╩è╦è╠è═è╬ ...
- êêè 3è3è3è3è3è3è3è3è3
- êêêê.
- êêêê.
- êêêê.
-
- Rule 6)ïTo divide two fractions that are both positive,ïyou should
- divide them like we did in the Elementary Level.ïTo divide two
- fractions that are both negative, you should change the operation to
- multiplication and invert the second fraction like we did in the
- Elementary Level.ïThen you should multiply the two numerators and the
- two denominators remembering that the product or quotient of two nega-
- tive numbers is positive.ïThen, cancel like factors and simplify.
-
- Examples
-
- ï1) Both fractions positive.
-
- ï5è 9ê 5è15ê5∙15êï5∙3∙5êè 25êè25
- # ── ÷ ──è=è── ∙ ──è=è────è=è─────────è=è───────è=è──
- 12è15ê12è 9ê12∙9ê2∙2∙3∙3∙3ê2∙2∙3∙3ê36
-
- 2) Both fractions negative.
-
- è -2è-3ë -2è8ê -2∙8ê -2∙2∙2∙2ê-16ê16
- #è ── ÷ ──è=ï── ∙ ─è=è──────è=è────────è=è───è=è──
- ë9è 8ê9ï-3ê9∙(-3)ê3∙3∙(-3)ê-27ê27
-
- Rule 7)ïTo divide two fractions that have different signs, you should
- change the operation to multiplication and invert the second fraction.
- Then, you should multiply the two numerators and the two denominators
- remembering that the product or quotient of a positive number and a
- negative number is negative.
-
- 3) One fraction positive and the second fraction negative.
-
- êè2è10ê2è-3ê2∙(-3)ê2∙(-3)ê-3
- #êè─ ÷ ──è=è─ ∙ ──è=è──────è=è──────è=è──
- êè7è-3ê7è10ê 7∙10êï7∙2∙5ê35
-
- 4) The first fraction negative and the second fraction positive.
-
- ê -1è 5ê-1è12ê-1∙12ê-1∙2∙2∙3ê-3
- #ê ── ÷ ──è=è── ∙ ──è=è─────è=è────────è=è──
- êï4è12ê 4è 5ê 4∙5êè2∙2∙5êï5
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