Algebra - GRE Quantitative Reasoning

100 miles = 528,000 feet. To put a number in scientific notation, we put a decimal point to the right of our first number, giving us 5.28. We then multiply by 10 to whatever power necessary to make our decimal equal the value we are looking for. For 5.28 to equal 528,000 we must multiply by $10^5$.

Therefore, our final answer becomes:

This question requires you to have an understanding of scientific notation. Begin by multiplying the two numbers:

To use scientific notation, the number to the left of the decimal has to be between 1 and 10. In this case, we are looking to move the decimal place until we are left with 9 on the left of the decimal. Count the number of places that the decimal will have to move. In this case, it is five. Therefore:

Note: The notation is raised to a negative power because we moved the decimal from left to right.

With this problem the first thing to do is cancel out variables. The x2 can all be divided by each other because they are present in each system. The equation will now look like this:

Now we can see that the equation can all be divided by y, leaving the answer to be:

_x_2 – _y_2 can be also expressed as (x + y)(x – y).

Therefore, the fraction now can be re-written as (x + y)(x – y)/(x + y).

This simplifies to (x – y).

Following this equation, you divide 4 by 8 to get 1/2. When a variable is raised to an exponent, and you are dividing, you subtract the exponents, so 6 – 3 = 3.

125 goes into 2000 evenly 16 times. 1/16 is the fraction in its simplest form.

120 goes into 6000 evenly 50 times, so we get 1/50 as our simplified fraction.

(2_x_ + 4)/(x + 2)

To simplify you must first factor the top polynomial to 2(x + 2). You may then eliminate the identical (x + 2) from the top and bottom leaving 2.

Set up the conversions as fractions and solve:

$\frac{20m}{1sec}$times $\frac{60sec^}{1min}$times $\frac{1km}{1000m}$times $\frac{10min}{1}$

To simplify exponents which are being divided, subtract the exponents on the bottom from exponents on the top. Remember that only exponents with the same bases can be simplified

Factor both the numerator and the denominator:

$$\frac{2(x^{2}$$$-4)(x^{2}$$+4)}{2(x^{2}$-4)}

After reducing the fraction, all that remains is:

$(x^{2}$+4)

Notice that the term appears frequently. Let's try to factor that out:

Now multiply both the numerator and denominator by the conjugate of the denominator:

The numerator and denominator are both divisible by 12. Thus, we divide both by 12 to get our final answer.

If we instead divide by another common factor, we may need to complete the process again to make sure that we have completely reduced the fraction.

In mathematical words we get the following:

This can be solved using 2 methods.

The most time-efficient solution would recognize that is the largest value and nearly equals the sum the other fraction by itself.

The more time consuming method would be to convert each fraction to decimal form and calculate the sum of each quantity.

Quantity A:

Quantity B:

When we factor the numerator and denominator, we get:

.

After cancelling , we are left with .

With common denominators, the range is from

or

.

The only fraction that falls in either of these ranges is .

Take the values of y that are possible, i.e. 2 and 3, and plug them into the first inequality. First, plug in 2. 2 – 3x > 21. Subtract 2 from both sides, and then divide by –3. Don't forget that when you divide or multiply by a negative number in an inequality you must flip the inequality sign. Thus, x < –19/3. Now plug in 3. We find, following the same steps, that when y=3, x < –6. Thus –7 is the correct answer.

If each pencil sells at 50 cents, x pencils will sell at 50x. The smallest value of x such that

50xgeq 1200+20x

xgeq 40

The answer is:

y-7< x+2y-14

-y-7< x-14

-1(-y< x-7)

y > -x+7

From the equation we can see that the slope is –1.