PSAT Math : Expressions
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Example Questions
Example Question #41 : How To Evaluate Algebraic Expressions
The function 
This is a simple substitution problem. Begin by setting the function 
Solve for 
A common mistake at this point is to believe that you have finished the question. We are given that 
Subtract 2 from both sides:
The answer is 
Example Question #421 : Algebra
Which of the following numbers is eight more than half of itself?
24
16
10
4
8
16
Word problems like this are a common occurrence on the PSAT. Begin by setting the number we are looking for, let's call it 
Move all terms with the variable to one side:
Multiply both sides by 2:
The correct answer is 16.
Example Question #41 : Expressions
Fahrenheit temperature can be converted to its Celsius equivalent using the formula
Celsius temperature can be converted to its Fahrenheit equivalent using the formula
Mercury boils at 
None of the other responses is correct.
The formula to use is
Substitute 357 for 
To the nearest degree, this is 
Example Question #1 : How To Simplify An Expression
Increase 
A number increased by 70% is equivalent to 100% of the number plus 70% of the number. This is taking 170% of the number, or, equivalently, multiplying it by 1.7.
Therefore, 
Example Question #422 : Algebra
Which of the following phrases can be written as the algebraic expression 
The cube of the difference of a number and nineteen
Nineteen less than the cube of a number
Three times the difference of nineteen and a number
The cube of the difference of nineteen and a number
Three times the difference of a number and nineteen
The cube of the difference of a number and nineteen
Example Question #423 : Algebra
Which of the following phrases can be written as the algebraic expression 
Three times the difference of a number and seventeen
The cube of the difference of a number and seventeen
Three times the difference of seventeen and a number
Seventeen decreased by the cube of a number
The cube of the difference of seventeen and a number
Seventeen decreased by the cube of a number
Example Question #1 : How To Simplify An Expression
Which of the following operations could represent the expression 
7 more than 2 times the square of x
7 less than the square of 2x
2 times 7 less than the square of x
2 times 7 more than the square of x
7 more than the square of 2x
7 more than 2 times the square of x
Begin by putting the equation given into your own words. It might sound something similar to:
2 times x squared plus 7
Now, go through each answer choice and see if any of them are similar to this. We immediately see that the answer "7 more than 2 times the square of x" is similar to what we came up with. Let's do a quick run through of the other choices to be sure of our choice:
"2 times 7 more than the square of x" is equal to 
"2 times 7 less than the square of x" is equal to 
"7 more than the square of 2x" is equal to 
"7 less than the square of 2x" is equal to 
The only answer that works is "7 more than 2 times the square of x". This is the correct answer.
Example Question #1 : How To Simplify An Expression
What does 
When solving a complex expression, remember the acronym PEMDAS (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction). Reading left to right, begin by doing all operations within the innermost Parentheses first:
Continue simplifying using the acronym PEMDAS:
The expression is equal to -63.
Example Question #1 : How To Add Rational Expressions With A Common Denominator
Simplify.
Same denominator means you add straight across the numerators, keeping the denominator the same.
Add like terms.
Final Answer.
Example Question #1 : How To Add Rational Expressions With A Common Denominator
Simplify.
Check for same Denominator
Add like terms
Check for GCF or if the expression can be factored
After factoring, divide out like terms.
Final Answer
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