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Example Question #33 : Algebraic Functions
In the xy-plane, a line with the equation crosses the y-axis at the point with the coordinates (m, n). What is the value of n?
0
–6
6
3
–6
This problem states that the given line crosses the y-axis at a certain point (m, n). By crossing the y-axis, we know that this point must be the y-intercept of this line. All y-intercepts lie on the y-axis and, therefore, have an x-coordinate of 0. If we plug in 0 for x in the equation of the line, , we will get
y = –6
The y-intercept must be at the point
(0, –6)
so n must be –6.
Example Question #2782 : Sat Mathematics
If and
. What is
?
Plugging in for
and 7 for
into
and solving for
, we obtain
.
Example Question #2781 : Sat Mathematics
Solve for :
.
Solving for yields
.
Example Question #2782 : Sat Mathematics
if and
, solve
.
We are solving for a composite function by substituting into
to get:
before simplification.
Example Question #2785 : Sat Mathematics
If where
is an integer, which of the following could be a value of
?
I.
II.
III.
II only
I only
I, II and III
I and III only
II and III only
II and III only
Choice I is incorrect because to equal 0, , and since
is an integer, this cannot be true.
Choice II is correct because when
or
.
Choice III is correct because when
or
.
Example Question #2783 : Sat Mathematics
Jamie is three times her little brother's age, and her little brother is two years younger than his older brother. Collectively, the three of them are 27 years old. How old is Jamie?
None of the available answers
The algebraic expression for being Jamie's youngest brother's age is:
Jamie's youngest brother is five, the next oldest brother is seven, and Jamie is 15.
Example Question #2784 : Sat Mathematics
Consider the function defined as follows:
Find:
The notation used above can be confusing. Let:
We can now find the answer by substituting the appropriate values into the equation:
Therefore:
Finally:
Example Question #2785 : Sat Mathematics
Solve for .
To solve for , we actually have to solve for
, when
. We simply replace any
with a
.
The answer of when
is
.
Example Question #2663 : Act Math
If f(x)=3x and g(x)=2x+2, what is the value of f(g(x)) when x=3?
22
20
18
24
24
With composition of functions (as with the order of operations) we perform what is inside of the parentheses first. So, g(3)=2(3)+2=8 and then f(8)=24.
Example Question #2664 : Act Math
g(x) = 4x – 3
h(x) = .25πx + 5
If f(x)=g(h(x)). What is f(1)?
19π – 3
4
π + 17
13π + 3
42
π + 17
First, input the function of h into g. So f(x) = 4(.25πx + 5) – 3, then simplify this expression f(x) = πx + 20 – 3 (leave in terms of π since our answers are in terms of π). Then plug in 1 for x to get π + 17.
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