ISEE Lower Level Math : Algebraic Concepts

Study concepts, example questions & explanations for ISEE Lower Level Math

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Example Questions

Example Question #91 : Equations

If  and , what is ?

Possible Answers:

Correct answer:

Explanation:

Sometimes we use letters instead of numbers if we don't know what number ought to go in a certain place. Saying "" means that something plus eight equals fifteen, but we aren't yet certain what that "something" is. When we can, we solve the puzzle of what number that letter could be replaced with. 

. , so  must be replaced by .

. , so  must be replaced by  also.

We're looking for . To find this, we replace the letters with the numbers we found.  and  both equal , so

, so . The correct answer is

Example Question #91 : Equations

Solve the following equations: 

Possible Answers:

Correct answer:

Explanation:

To solve the equation you must get  by itself.  The first step is to add  to both sides to offset the  resulting in .  The final step to get  byitself is to divide both sides by  which gives us .

Example Question #91 : Equations

Solve the following equation for c when .

Possible Answers:

Correct answer:

Explanation:

Solve the following equation for c when .

We can begin by plugging in 6 for b:

Simplify

Next, take the square root of both sides to get:

Note that our answer is plus or minus five, because squaring positive or negative five will yield 25.

Example Question #94 : Equations

Solve the following equation for z when x=5, and y=2.

Possible Answers:

Correct answer:

Explanation:

Solve the following equation for z when x=5, and y=2.

Let's begin by dividing the whole equation by 3. This will get "z" by itself and make our equaiton easier to work with.

Next, plug our given values in and simplify

So, we get:

Example Question #95 : Equations

If Timmy had  pieces of gum yesterday, and only  today, how many pieces did Timmy lose overnight?

Possible Answers:

Correct answer:

Explanation:

To solve a word problem with an unknown quantity, treat the unknown quantity as a variable.  The best equation for the problem above is:  

 

Use algebra to solve.

Example Question #96 : Equations

An unknown number of children are on the bus on their way home from school.  At the first stop, eight children get off the bus, at the second, fifteen get off, and at the third and final stop four children get off.  There are no children left on the bus.  How many were on the bus at the start of its route?  

Possible Answers:

Correct answer:

Explanation:

To solve a word problem with an unknown quantity, treat the unknown quantity as a variable.  The best equation for the problem above is:  

Example Question #91 : Equations

Mrs. Franklin has twenty stickers, and she wants to distribute them evenly among four students.  How many stickers will each student receive?

Possible Answers:

Correct answer:

Explanation:

To solve a word problem with an unknown quantity, treat the unknown quantity as a variable.  The best equation for the problem above is:  

 

Example Question #92 : Equations

If it costs twelve dollars to buy an action figure, and Joanna bought eight action figures, how much money did she pay for them?

Possible Answers:

Correct answer:

Explanation:

To solve a word problem with an unknown quantity, treat the unknown quantity as a variable.  The best equation for the problem above is:  

 

Example Question #99 : Equations

Solve the following equation if .

 

Possible Answers:

Correct answer:

Explanation:

Since you already know that  is , you just plug it in for the variable in the equation.

This gives you,

 .  

Performing algebraic operations to simplify results in the following.

 

and 

 

Therefore,

 .

Example Question #94 : Equations

If the side of a square is , and the square’s area is 144 feet, what is the value of ?

Possible Answers:

Correct answer:

Explanation:

The formula for the area of a square is length times width.  

 where  thus the area formula becomes .

The question gives,

 and 

In order to solve this, substitute in the given information into the area formula.

From here find the square root of both sides. 

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