The graph of f(x) = 0.4x is replaced by the graph of g(x) = 0.4x + k. If g(x) is obtained by shifting f(x) up by 4 units, then what is the value of k?

The value of k=4

Step-by-step explanation:

we have

f(x)=0.4x

This function represent a linear direct variation (The line passes through the origin)  

we know that  

If f(x) is shifting up by 4 units  

then  

The y-intercept of the function will be the point (0,4)  

therefore  

The function g(x) will be  > g(x)=0.4x+4 (equation of the line into slope

intercept form)

The rule of the translation

f(x) > g(x)

(x,y) > (x,y+4)

The translation is 4 units up

therefore

The value of k=4

let's add {f(x)=x+1}f(x)=x+1 and {g(x)=2x}g(x)=2x together to make a new function.

f(x)+g(x) =(x+1)+(2x)=x+1+2x=3x+1

let's call this new function hh. so we have:

{h(x)}={f(x)}+{g(x)}{=3x+1}h(x)=f(x)+g(x)=3x+1

we can also evaluate combined functions for particular inputs. let's evaluate function hh above for x=2x=2. below are two ways of doing this.

method 1: substitute x=2x=2 into the combined function hh.

h(x)

h(2)

​    

=3x+1

=3(2)+1

=7

​ since h(x)=f(x)+g(x)h(x)=f(x)+g(x), we can also find h(2)h(2) by finding f(2) +g(2)f(2)+g(2).

first, let's find f(2)f(2):

f(x)

f(2)

​    

=x+1

=2+1

=3

​  

now, let's find g(2)g(2):

g(x)

g(2)

​    

=2x

=2⋅2

=4

​  

so f(2)+g(2)=3+4=\greend7f(2)+g(2)=3+4=7.

notice that substituting x =2x=2 directly into function hh and finding f(2) + g(2)f(2)+g(2) gave us the same answer!

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step-by-step explanation: