ISEE Middle Level Math : ISEE Middle Level (grades 7-8) Mathematics Achievement

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

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Example Questions

Example Question #62 : Operations

\(\displaystyle -4x (-2x^{2} +3y -4) =\)

Possible Answers:

\(\displaystyle 8x^{3} +12xy -16x\)

\(\displaystyle -8x^{3} -12xy + 16y\)

\(\displaystyle 8x^{3} -12xy +16x\)

\(\displaystyle 8x^{2} -12xy +16x\)

Correct answer:

\(\displaystyle 8x^{3} -12xy +16x\)

Explanation:

First distribute the \(\displaystyle -4x\) to all terms in the parenthesis.

\(\displaystyle (-4x \times -2x^{2}) + (-4x \times 3y) + (-4x \times -4)\)

\(\displaystyle (-4x \times -2x^{2}) = 8x ^{1+2} = 8x^{3}\)  (When multiplying variables with exponents, the exponents are added together).

\(\displaystyle (-4x \times 3y) = -4\times 3 \times x\times y = -12xy\)

\(\displaystyle -4x (-4) = 16x\)

\(\displaystyle 8x^{3} -12xy + 16x\)

Example Question #66 : Variables

\(\displaystyle (-6x^{4}y^{2}) \times (-3x^{2}y^{2})=\)

Possible Answers:

\(\displaystyle 18x^{8}y^{4}\)

\(\displaystyle -9x^{6}y^{4}\)

\(\displaystyle -18x^{6}y^{4}\)

\(\displaystyle 18x^{6}y^{4}\)

Correct answer:

\(\displaystyle 18x^{6}y^{4}\)

Explanation:

To solve \(\displaystyle (-6x^{4}y^{2}) \times(-3x^{2}y^{2})\)

Separate the parts of the terms.  Multiply the coefficients:

\(\displaystyle -6 \times - 3 = 18\)

Multiply the terms with \(\displaystyle x\) as the variable. When multiplying, the exponents get added.

\(\displaystyle x^{4}\times x^{2} = x^{4+2} = x^{6}\)

Multiply the terms with \(\displaystyle y\) as the variable. When multiplying, the exponents get added.

\(\displaystyle y^{2}\times y^{2} = y^{2+2} = y^{4}\)

Put it all together:

\(\displaystyle 18x^{6}y^{4}\)

 

 

 

Example Question #61 : Variables

The length of a rectangle is \(\displaystyle 4y\) and the width is \(\displaystyle 9{y}.\) What is the area of this rectangle?

Possible Answers:

\(\displaystyle 26y\)

\(\displaystyle 36y^{2}\)

\(\displaystyle 13y\)

\(\displaystyle 36y\)

Correct answer:

\(\displaystyle 36y^{2}\)

Explanation:

The formula for the Area of a rectangle is length times width or l x w.  Multiply the length which is \(\displaystyle 4y\) times the width which is \(\displaystyle 9y.\)

First multiply

\(\displaystyle 4 \times 9 =36\)

Then multiply the variables; add the exponents:

\(\displaystyle y\timesy = y^{1+1} = y^{2}\)

Area or A of the rectangle is

\(\displaystyle 36y^{2}\)

Example Question #68 : Variables

The length of a rectangular prism is \(\displaystyle 8y\) centimeters.  The width is \(\displaystyle 5y\) centimeters. The height is \(\displaystyle 6y\) centimeters. Find the volume of this rectangular prism.

Possible Answers:

\(\displaystyle 9x^{3}centimeters^{3}\)

\(\displaystyle 240 centimeters^{3}\)

\(\displaystyle 240x^{3} centimeters^{3}\)

\(\displaystyle 19x^{3} centimeters ^{3}\)

Correct answer:

\(\displaystyle 240x^{3} centimeters^{3}\)

Explanation:

The volume of a rectangular prism is determined by using the formula

V = length x width x height

\(\displaystyle 8 \times 6\times 5 = 240\)

\(\displaystyle x \ast x \ast x = x^{1+1+1} =x^{3}\)

\(\displaystyle 240x^{3} centimeters^{3}\)

Example Question #2181 : Isee Middle Level (Grades 7 8) Mathematics Achievement

Multiply the following:

\(\displaystyle x \cdot 3x\)

Possible Answers:

\(\displaystyle 3x\)

\(\displaystyle x^2\)

\(\displaystyle 3\)

\(\displaystyle 3x^2\)

\(\displaystyle 4x\)

Correct answer:

\(\displaystyle 3x^2\)

Explanation:

When multiplying variables, we multiply them together just like we would integers.  We have

\(\displaystyle x \cdot 3x\)

 

The first term isn't showing a coefficient, so it is automatically 1.  So,

\(\displaystyle 1x \cdot 3x\)

 

Now, we will multiply the coefficients together, then we multiply the variables together.

So, we get

\(\displaystyle 1x \cdot 3x = (1 \cdot 3)(x \cdot x) = 3x^2\)

Example Question #70 : Variables

Simplify the following expression:

\(\displaystyle 9x^3t^7*4x^5t^{12}\)

Possible Answers:

\(\displaystyle 36x^8t^{19}\)

\(\displaystyle 9x^8t^{19}\)

\(\displaystyle 36x^8t^{84}\)

\(\displaystyle 13x^8t^{19}\)

Correct answer:

\(\displaystyle 36x^8t^{19}\)

Explanation:

Simplify the following expression:

\(\displaystyle 9x^3t^7*4x^5t^{12}\)

Let's begin by rewriting the expression with similar terms next to each other.

\(\displaystyle (9*4)(x^3*x^5)(t^7*t^{12})\)

Next, multiply the terms out.

Our first pair of terms is just like regular multiplication.

For the next two terms, we need to add the exponents. 

In doing so, we get:

\(\displaystyle 36x^8t^{19}\)

Example Question #2181 : Isee Middle Level (Grades 7 8) Mathematics Achievement

Simplify the following statement

\(\displaystyle (14b^2t^5)(2b^3t^9)\)

Possible Answers:

\(\displaystyle 28b^4t^{4}\)

\(\displaystyle 14b^5t^{14}\)

\(\displaystyle 28b^5t^{14}\)

\(\displaystyle 28t^5b^{14}\)

Correct answer:

\(\displaystyle 28b^5t^{14}\)

Explanation:

Simplify the following statement

\(\displaystyle (14b^2t^5)(2b^3t^9)\)

To multiply these terms, first multiply the 2 and the 14

\(\displaystyle 28(b^2t^5)(b^3t^9)\)

Next, we can combine the b's and the t's by adding together their exponents.

\(\displaystyle 28(b^2t^5)(b^3t^9)=28b^5t^{14}\)

So our answer is:

\(\displaystyle 28b^5t^{14}\)

Example Question #71 : Algebraic Concepts

Combine the following terms:

\(\displaystyle 5q^3*8q^4*9q^{11}\)

Possible Answers:

\(\displaystyle 360q^{7}\)

\(\displaystyle 360q^{18}\)

\(\displaystyle 360q^{12}\)

\(\displaystyle 36q^{18}\)

Correct answer:

\(\displaystyle 360q^{18}\)

Explanation:

Combine the following terms:

\(\displaystyle 5q^3*8q^4*9q^{11}\)

Let's begin by multiplying the coefficients (numbers out in front)

\(\displaystyle 5*8*9=40*9=360\)

So our answer must have 360 in front.

Next, let's multiply our q's. To do so, we need to add up our exponents.

\(\displaystyle q^3*q^4*q^{11}=q^{3+4+11}=q^{18}\)

So, put it together to get:

\(\displaystyle 360q^{18}\)

Example Question #71 : Algebraic Concepts

\(\displaystyle x^{2} = 64\). Evaluate \(\displaystyle x^{4}\).

Possible Answers:

\(\displaystyle 4,096\)

\(\displaystyle 32\)

\(\displaystyle 8\)

\(\displaystyle 512\)

Correct answer:

\(\displaystyle 4,096\)

Explanation:

\(\displaystyle x^{2} = 64\), so either \(\displaystyle x = \sqrt{64} = 8\) or \(\displaystyle x = - \sqrt{64} =- 8\).

If the former is true, 

\(\displaystyle x^{4} = 8^{4} = 8 \cdot 8 \cdot 8 \cdot 8 = 4,096\).

If the latter is true, then, since an even-numbered power of any number is positive, 

\(\displaystyle x^{4} =( - 8)^{4} = 8^{4} = 4,096\).

Example Question #71 : How To Multiply Variables

Simplify the following expression

\(\displaystyle 54x^3*8x^2*\frac{x^2}{9}\)

Possible Answers:

\(\displaystyle 48x^7\)

\(\displaystyle 540x^7\)

\(\displaystyle 48x^{12}\)

\(\displaystyle 1244x^{12}\)

Correct answer:

\(\displaystyle 48x^7\)

Explanation:

Simplify the following expression

\(\displaystyle 54x^3*8x^2*\frac{x^2}{9}\)

Let's begin by grouping our x's and our coefficients

\(\displaystyle (54*8*\frac{1}{9})(x^3*x^2*x^2)\)

We can combine our coefficents by multiplying them, and we can combine the x's by adding the exponents

\(\displaystyle (54*\frac{1}{9}*8)(x^7)=(6*8)x^7=48x^7\)

So, our answer is:

\(\displaystyle 48x^7\)

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