All PSAT Math Resources
Example Questions
Example Question #492 : Algebra
Solve for :
Combining the powers, we get .
From here we can use logarithms, or simply guess and check to get .
Example Question #13 : Exponents
If and are positive integers, and , then what is in terms of ?
is equal to which is equal to . If we compare this to the original equation we get
Example Question #1111 : Psat Mathematics
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. –5
II. –7
III. –9
II and III only
I only
I and II only
I, II and III only
II only
II 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 #1112 : Psat Mathematics
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 #1113 : Psat Mathematics
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 #1114 : Psat Mathematics
Solve:
Subtract the denominator exponent from the numerator's exponent, since they have the same base.
Example Question #1115 : Psat Mathematics
54 / 25 =
10
50
54 / 5
25
5
25
25 = 5 * 5 = 52. Then 54 / 25 = 54 / 52.
Now we can subtract the exponents because the operation is division. 54 / 52 = 54 – 2 = 52 = 25. The answer is therefore 25.
Example Question #1 : How To Divide Exponents
For all real numbers n, (2n * 2) / (2n * 2n) =
2n
21 – n
2
2n/2n
2n – 1
21 – n
(2n * 2) / (2n * 2n) simplifies to 2/2n or 21/2n.
When dividing exponents with the same base, you subtract the divisor from the dividend, giving 21–n.
Example Question #2 : How To Divide Exponents
If x9/x3 = xn, solve for n.
6
9
12
7
3
6
When dividing terms with the same base, we can subtract the exponents:
9 – 3 = 6
Example Question #3 : How To Divide Exponents
Simplify the following expression: (x2y4)/(x3y3z2)
y/xz2
z2xy
xy/z2
xz2/y
y/xz2
According to the rules of exponents, ax/ay = ax-y
In this expression, we can follow this rule to simplify x2/x3 and y4/y3
x2–3 = x–1 = 1/x. y4–3 = y1 = y.
Therefore, y/xz2