IXL - Solve quadratic equations: word problems (Algebra 1 practice)

To help the plants in his garden grow, Andrew decides to start composting. He wants to build a compost box in the shape of a rectangular prism that holds 30 gallons, or 6,930 cubic inches, of compost. He wants the box to be 40 inches long to fit perfectly alongside his shed. The height of the box will be equal to its width.

Which equation can you use to find the width of the compost box?

6,930

To the nearest tenth of an inch, what is the width of the compost box?

inches

ref_doc_title.

Learn with an example

question

Mack's Knick-Knacks is having a clearance sale on costume jewelry sets next week. The manager wants to find how much to charge per set in order to sell

100

worth. Based on previous clearance events, the manager knows he can use the expression

–

to find the number of sets he will sell based on a set's price,

Which equation can the manager use to find the price per set needed to sell

100

worth?

100

(

–

)

100

(

–

)

To the nearest dollar, what is the highest price the manager can use to sell

100

worth of costume jewelry sets?

solution

To find the price per set, first write an equation. Revenue, or the total amount of money made from jewelry sets, is equal to the price per set times the number of jewelry sets sold.

revenue

price per set

number of jewelry sets

You want to know when the revenue will be

100

and the expression

–

can be used to predict the number of jewelry sets sold. The price per set,

is the variable.

100

(

–

)

Now, solve for

Start by writing the equation in standard form.

100

(

–

)

100

–

100

To solve for

you can use the quadratic formula with

–

and

–

100

–

(

)

(

)

–

(

–

)

(

–

100

)

(

–

)

–

2,825

–

2,825

–

or p

–

2,825

–

1.5606… or p

9.1536…

So, to the nearest dollar, the highest price the manager can use to sell

100

worth of costume jewelry sets is

Looking for more? Try this:

$Confetti$

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Teacher tools

Work it out

Not feeling ready yet? These can help:

Z.6Solve a quadratic equation using the quadratic formula

Z.3Solve a quadratic equation by factoring

Z.1Solve a quadratic equation using square roots

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