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Algebraic Simplification and Expansion — Free MYP5 Mathematics (Standard) Practice Questions
1QuestionCombining Like Terms After ExpansionConcept Practice
4 marks~6 minCriterion C
A mobile data company advertises two pricing plans:
f(x)=2(x+3)andg(x)=2x+6
where x is the number of gigabytes used and the output is the cost in dollars.
a
Show that f(x)=2x+6 by expanding using the distributive property. [1]
b
Explain why f(x) and g(x) represent the same function for all values of x. [1]
c
A customer claims that Plan f is cheaper than Plan g. Advise the customer whether this claim is correct, and what it means for their choice between the two plans. [2]
Solutions
2QuestionCombining Like Terms After ExpansionAssessment Practice
4 marks~6 minCriterion D
A small business owner models monthly profit (in dollars) as P(x)=(x+50)(200−2x), where x is the number of one-dollar price increases applied to the product. The model assumes demand decreases linearly as price rises.
a
Expand P(x)=(x+50)(200−2x) and write it in the form ax2+bx+c, stating the values of a, b, and c. [2]
b
Advise the business owner whether this model is a sufficient basis for determining an optimal pricing strategy. Refer to both the mathematical structure of P(x) and real-world factors the model does not capture. [2]
Solutions
3QuestionExpanding Double Brackets BinomialsConcept Practice
4 marks~6 minCriterion A
A farmer models the area of a rectangular field (in square metres) using the expression (x+5)(x+3), where x is a positive side-length in metres.
a
Expand and simplify (x+5)(x+3). [2]
b
The farmer needs a field with an area of at least 77 m2. Given that x=7, justify whether this field meets the requirement, using your expression from part (a). [1]
c
Discuss one strength and one limitation of using this algebraic expression as a model for planning crop planting. [1]
Solutions
4QuestionCombining Like Terms After ExpansionAssessment Practice
5 marks~8 minCriterion B
Consider the following expansions:
(x+1)(x+2)=x2+3x+2
(x+2)(x+3)=x2+5x+6
(x+3)(x+4)=x2+7x+12
(x+4)(x+5)=x2+9x+20
a
Using the pattern above, predict:
(i) the constant term in the expansion of (x+5)(x+6). [1]
(ii) the coefficient of x in the expansion of (x+5)(x+6). [1]
b
Deduce a general formula for (x+a)(x+b), showing full algebraic working. [2]
c
Apply your formula to expand (x+10)(x+15). [1]
d
A student claims: "The coefficient of x is always equal to the product of the two constants." Evaluate this claim using your general formula and one example from the table above. [2]
(e) A rectangular garden has side lengths (x+10) metres and (x+15) metres. The designer states the garden can only be built if its area exceeds 500m2 when x=10. Justify whether the designer's condition is met. [1]