The year before last, the age of the father is four times the age of the son; the year after, the age of the father is three times the age of the son. How old is father this year?
前年，父亲年龄是儿子年龄的4倍；后年，父亲年龄是儿子年龄的3倍．父亲今年多少岁．
<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<gadget id="calculator">8 / 1</gadget>
<output>8</output>

<gadget id="calculator">4 * 8</gadget>
<output>32</output>

<gadget id="calculator">32 + 2</gadget>
<output>34</output>

<result>34</result>