All PSAT Math Resources
Example Question #1 : How To Subtract Exponents
If m and n are integers such that m < n < 0 and m2 – n2 = 7, which of the following can be the value of m + n?
I and II only
II and III only
I, II and III only
m and n are both less than zero and thus negative integers, giving us m2 and n2 as perfect squares. The only perfect squares with a difference of 7 is 16 – 9, therefore m = –4 and n = –3.
Example Question #16 : Exponential Operations
To simplify, we can rewrite the numerator using a common exponential base.
Now, we can factor out the numerator.
The eights cancel to give us our final answer.
Example Question #17 : Exponential Operations
If , then what is ?
Follow the order of operations by solving the expression within the parentheses first.
Return to solve the original expression.
Example Question #18 : Exponential Operations
Subtract the denominator exponent from the numerator's exponent, since they have the same base.