// Numbas version: finer_feedback_settings {"name": "7d. Adding harder algebraic fractions", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "7d. Adding harder algebraic fractions", "tags": [], "metadata": {"description": "

(ax+b)/(mx+n)+(cx+d)/(px+q)

", "licence": "Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International"}, "statement": "

Express the following as a single fraction:

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\\[\\simplify[basic,unitFactor,zeroTerm,zeroFactor]{({a}{L}+{b})/({m}{L}+{n})+({c}{L}+{d})/({p}{L}+{q})}\\]

\n

\n

Simplify your answer where possible.

", "advice": "

Adding algebraic fractions is the same as adding ordinary fractions. First we need to write both fractions over the same denominator by multiplying the top and bottom of both fractions

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\\[\\simplify[basic,unitFactor,zeroTerm,zeroFactor]{({a}{L}+{b})/({m}{L}+{n})+({c}{L}+{d})/({p}{L}+{q})}=\\simplify[basic,unitFactor,zeroTerm,zeroFactor]{({p}{L}+{q})({a}{L}+{b})/(({p}{L}+{q})({m}{L}+{n}))+({m}{L}+{n})({c}{L}+{d})/(({m}{L}+{n})({p}{L}+{q}))}\\]

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Finally we add the numerators together and simplify to get

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\\[\\simplify[unitFactor,zeroTerm,zeroFactor]{({p}{L}+{q})({a}{L}+{b})/(({p}{L}+{q})({m}{L}+{n}))+({m}{L}+{n})({c}{L}+{d})/(({m}{L}+{n})({p}{L}+{q}))}
=\\simplify[unitFactor,zeroTerm,zeroFactor]{({a*p}{L}^2+{a*q+b*p}{L}+{b*q}+{m*c}{L}^2+{m*d+n*c}{L}+{n*d})/(({m}{L}+{n})({p}{L}+{q}))}\\]
\\[=\\simplify{({a*p}{L}^2+{a*q+b*p}{L}+{b*q}+{m*c}{L}^2+{m*d+n*c}{L}+{n*d})/({m*p}{L}^2+{m*q+n*p}{L}+{n*q})}.\\]

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