All SAT Math Resources
Example Questions
Example Question #1 : Rational Expressions
9/5
37/15
–37/15
–11/5
–9/5
–11/5
Example Question #1 : Expressions
If Jill walks in , how long will it take Jill to walk ?
To solve this, we need to set a proportion.
Cross Multiply
So it will take Jill to walk
Example Question #2471 : Sat Mathematics
If , then which of the following must be also true?
Example Question #2472 : Sat Mathematics
Which of the following is equivalent to ? Assume that denominators are always nonzero.
We will need to simplify the expression . We can think of this as a large fraction with a numerator of and a denominator of .
In order to simplify the numerator, we will need to combine the two fractions. When adding or subtracting fractions, we must have a common denominator. has a denominator of , and has a denominator of . The least common denominator that these two fractions have in common is . Thus, we are going to write equivalent fractions with denominators of .
In order to convert the fraction to a denominator with , we will need to multiply the top and bottom by .
Similarly, we will multiply the top and bottom of by .
We can now rewrite as follows:
=
Let's go back to the original fraction . We will now rewrite the numerator:
=
To simplify this further, we can think of as the same as . When we divide a fraction by another quantity, this is the same as multiplying the fraction by the reciprocal of that quantity. In other words, .
=
Lastly, we will use the property of exponents which states that, in general, .
The answer is .
Example Question #2473 : Sat Mathematics
Simplify (4x)/(x2 – 4) * (x + 2)/(x2 – 2x)
(4x2 + 8x)/(x4 + 8x)
4/(x + 2)2
x/(x + 2)
x/(x – 2)2
4/(x – 2)2
4/(x – 2)2
Factor first. The numerators will not factor, but the first denominator factors to (x – 2)(x + 2) and the second denomintaor factors to x(x – 2). Multiplying fractions does not require common denominators, so now look for common factors to divide out. There is a factor of x and a factor of (x + 2) that both divide out, leaving 4 in the numerator and two factors of (x – 2) in the denominator.
Example Question #4 : Expressions
what is 6/8 X 20/3
6/8 X 20/3 first step is to reduce 6/8 -> 3/4 (Divide top and bottom by 2)
3/4 X 20/3 (cross-cancel the threes and the 20 reduces to 5 and the 4 reduces to 1)
1/1 X 5/1 = 5
Example Question #8 : Rational Expressions
Evaluate and simplify the following product:
The procedure for multplying together two rational expressions is the same as multiplying together any two fractions: find the product of the numerators and the product of the denominators separately, and then simplify the resulting quotient as far as possible, as shown:
Example Question #1 : How To Add Rational Expressions With A Common Denominator
Simplify the following rational expression: (9x - 2)/(x2) MINUS (6x - 8)/(x2)
Since both expressions have a common denominator, x2, we can just recopy the denominator and focus on the numerators. We get (9x - 2) - (6x - 8). We must distribute the negative sign over the 6x - 8 expression which gives us 9x - 2 - 6x + 8 ( -2 minus a -8 gives a +6 since a negative and negative make a positive). The numerator is therefore 3x + 6.
Example Question #2474 : Sat Mathematics
Simplify the following rational expression:
Since both fractions in the expression have a common denominator of , we can combine like terms into a single numerator over the denominator:
Example Question #3 : How To Add Rational Expressions With A Common Denominator
Simplify the following rational expression:
Since both rational terms in the expression have the common denominator , combine the numerators and simplify like terms:
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