I just finished doing my math study guide for a test and there is one question that I don't know how to do. It is:
f(x)=5-2x and g(x)=x^2=7x, find each value.
a. g(3)
b. f(2)+g(-1)
c g(2x)
I do not understand this at all, could someone explain this to me? Thank you.
So, this means you actually plug in the variables.
For example:
g(3) means for every x you see in g(x) you put a 3 in. Evaluate.
still don't get it
first of all , you have a typo in
g(x)=x^2=7x
I think you meant: g(x)=x^2+7x , since the + and the = are on the same key
you are given that
g(x) = x^2 + 7x
so you want g(3).
As Philip stated, wherever you had an x , now put in a 3
g(3) = 3^2 + 7(3)
= 9 + 21
= 90
so since f(x) = 5-2x
then f(2)+g(-1)
= 5 - 2(2) + (-1)^2 + 7(-1)
= 5 - 4 + 1 - 7
= -5
g(2x) , wherever I had an x, I now put in 2x
= (2x)^2 + 7(2x)
= 4x^2 + 14x
Of course! I'd be happy to help you understand these questions.
Let's break it down step by step:
a. g(3)
To find g(3), we substitute 3 into the equation g(x) = x^2 - 7x.
So, g(3) = 3^2 - 7(3).
This simplifies to g(3) = 9 - 21.
Therefore, g(3) = -12.
b. f(2) + g(-1)
To find f(2) + g(-1), we need to find the value of f(2) and g(-1), and then add them together.
f(x) = 5 - 2x, so we substitute 2 into the equation.
f(2) = 5 - 2(2) = 5 - 4 = 1.
Next, we find g(-1).
g(x) = x^2 - 7x, so we substitute -1 into the equation.
g(-1) = (-1)^2 - 7(-1) = 1 + 7 = 8.
Therefore, f(2) + g(-1) = 1 + 8 = 9.
c. g(2x)
To find g(2x), we substitute 2x into the equation g(x) = x^2 - 7x.
So, g(2x) = (2x)^2 - 7(2x).
This simplifies to g(2x) = 4x^2 - 14x.
And that's how you find each value for the given functions.