All SAT Math Resources
Example Questions
Example Question #12 : Algebraic Fractions
Which of the following provides the complete solution set for ?
No solutions
The absolute value will always be positive or 0, therefore all values of z will create a true statement as long as . Thus all values except for 2 will work.
Example Question #1 : How To Find Excluded Values
If the average (arithmetic mean) of , , and is , what is the average of , , and ?
There is not enough information to determine the answer.
If we can find the sum of , , and 10, we can determine their average. There is not enough information to solve for or individually, but we can find their sum, .
Write out the average formula for the original three quantities. Remember, adding together and dividing by the number of quantities gives the average:
Isolate :
Write out the average formula for the new three quantities:
Combine the integers in the numerator:
Replace with 27:
Example Question #2 : How To Find Excluded Values
Find the excluded values of the following algebraic fraction
The numerator cancels all the binomials in the denomniator so ther are no excluded values.
To find the excluded values of a algebraic fraction you need to find when the denominator is zero. To find when the denominator is zero you need to factor it. This denominator factors into
so this is zero when x=4,7 so our answer is
Example Question #2 : How To Find Excluded Values
For what value(s) of x is the function undefined?
When the denominator of a function is equal to 0, the function is undefined at that point. We can set x2-25 equal to 0 in order to find out what values of x make that true.
We can factor to solve for x.
is an incorrect answer because for this value of x, the function equals zero, but it is not undefined.
Example Question #2 : How To Find Excluded Values
Find the extraneous solution for
There are no extraneous solutions
Now lets plug these values into our original equation.
For
So this isn't an extraneous solution.
For
Since , is an extraneous solution.
Example Question #1 : Distributive Property
Example Question #1 : How To Use Foil In The Distributive Property
If , what is the value of ?
Remember that (a – b )(a + b ) = a 2 – b 2.
We can therefore rewrite (3x – 4)(3x + 4) = 2 as (3x )2 – (4)2 = 2.
Simplify to find 9x2 – 16 = 2.
Adding 16 to each side gives us 9x2 = 18.
Example Question #2 : How To Use Foil In The Distributive Property
If and , then which of the following is equivalent to ?
We are asked to find the difference between g(h(x)) and h(g(x)), where g(x) = 2x2 – 2 and h(x) = x + 4. Let's find expressions for both.
g(h(x)) = g(x + 4) = 2(x + 4)2 – 2
g(h(x)) = 2(x + 4)(x + 4) – 2
In order to find (x+4)(x+4) we can use the FOIL method.
(x + 4)(x + 4) = x2 + 4x + 4x + 16
g(h(x)) = 2(x2 + 4x + 4x + 16) – 2
g(h(x)) = 2(x2 + 8x + 16) – 2
Distribute and simplify.
g(h(x)) = 2x2 + 16x + 32 – 2
g(h(x)) = 2x2 + 16x + 30
Now, we need to find h(g(x)).
h(g(x)) = h(2x2 – 2) = 2x2 – 2 + 4
h(g(x)) = 2x2 + 2
Finally, we can find g(h(x)) – h(g(x)).
g(h(x)) – h(g(x)) = 2x2 + 16x + 30 – (2x2 + 2)
= 2x2 + 16x + 30 – 2x2 – 2
= 16x + 28
The answer is 16x + 28.
Example Question #2 : How To Use Foil In The Distributive Property
The sum of two numbers is . The product of the same two numbers is . If the two numbers are each increased by one, the new product is . Find in terms of .
Let the two numbers be x and y.
x + y = s
xy = p
(x + 1)(y + 1) = q
Expand the last equation:
xy + x + y + 1 = q
Note that both of the first two equations can be substituted into this new equation:
p + s + 1 = q
Solve this equation for q – p by subtracting p from both sides:
s + 1 = q – p
Example Question #5 : Distributive Property
Expand the expression:
When using FOIL, multiply the first, outside, inside, then last expressions; then combine like terms.