// Numbas version: exam_results_page_options {"name": "Expansion of two brackets: Linear 2", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"functions": {}, "name": "Expansion of two brackets: Linear 2", "tags": ["algebra", "algebraic manipulation", "expansion of brackets", "expansion of the product of two linear terms"], "advice": "\n

Using the method given by Show steps we have:

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\\[\\begin{eqnarray*}\\simplify[std]{ ({a}x+{b})({c}x+{d})}&=&\\simplify[std]{{a}x*({c}x+{d})+{b}({c}x+{d})}\\\\&=&\\simplify[std]{{a*c}x^2+{a*d}x+{b*c}x+{b*d}}\\\\&=&\\simplify[std]{{a*c}x^2+{(a*d+b*c)}x+{b*d}}\\end{eqnarray*}\\]

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$\\simplify[std]{({a}x+{b})({c}x+{d})}=\\;$[[0]].

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Your answer should be a quadratic in $x$ and should not include any brackets.

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You can click on Show steps for more information, but you will lose one mark if you do so.

\n ", "gaps": [{"notallowed": {"message": "

Do not include brackets in your answer. Input your answer as a quadratic in $x$, in the form $ax^2+bx+c$ for appropriate integers $a,\\;b,\\;c$.

", "showstrings": false, "strings": ["("], "partialcredit": 0.0}, "checkingaccuracy": 0.001, "vsetrange": [0.0, 1.0], "vsetrangepoints": 5.0, "checkingtype": "absdiff", "answersimplification": "std", "maxlength": {"length": 17.0, "message": "

Input your answer as a quadratic in $x$, in the form $ax^2+bx+c$ for appropriate integers $a,\\;b,\\;c$.

", "partialcredit": 0.0}, "answer": "{a*c}x^2+{b*c+a*d}x+{b*d}", "marks": 2.0, "type": "jme", "musthave": {"message": "

Input your answer as a quadratic in $x$, in the form $ax^2+bx+c$ for appropriate integers $a,\\;b,\\;c$.

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There are many ways to expand an expression such as $(ax+b)(cx+d)$.

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One way:

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\\[\\begin{eqnarray*} (ax+b)(cx+d)&=&ax(cx+d)+b(cx+d)\\\\&=&acx^2+adx+bcx+bd\\\\&=&acx^2+(ad+bc)x+bd\\end{eqnarray*}\\]

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Expand the following to give a quadratic in $x$.

", "variable_groups": [], "progress": "ready", "type": "question", "variables": {"a": {"definition": "random(-5..5 except 0)", "name": "a"}, "c": {"definition": "random(-5..5 except 0)", "name": "c"}, "b": {"definition": "random(-9..9 except [0,a])", "name": "b"}, "d": {"definition": "random(-9..9 except [0,c])", "name": "d"}}, "metadata": {"notes": "\n \t\t

15/08/2012:

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Added tags.

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Added description.

\n \t\t", "description": "

Expand $(ax+b)(cx+d)$.

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