Respuesta :

For this case we have the following functions:
 For [tex]- 4 \leq x \ \textless \ 3[/tex] : 
 [tex]y = x + 4 [/tex]
 For [tex]3 \leq x \ \textless \ 6[/tex] :
 [tex]y = 2x - 1 [/tex]
 What we need to know for this case is:
 Both functions are one lines
 Both functions have a positive slope
 Both functions are in a certain interval
 Answer:
 See attached image to see functions
Ver imagen carlosego
Ver imagen carlosego
ANSWER

To graph the function

[tex]f(x)=\left \{ {{x+4\:\:if\:\:-4\leq x<3}  \atop {2x-1\:\:if\:\:3\leq x<6}} \right.[/tex]

follow the steps below.

1. Find y- intercept by plugging in [tex]x=0[/tex].

[tex]x=0[/tex] is on the interval,  [tex]-4\leq x<3[/tex], so we substitute in to

[tex]f(x)=x+4[/tex]

[tex]\Rightarrow f(0)=0+4[/tex]

[tex]\Rightarrow f(0)=4[/tex]

Hence the y-intercept is [tex](0,4)[/tex]

2. Find x-intercept by setting [tex]f(x)=0[/tex]

This implies that

[tex]x+4=0,[/tex] on [tex]-4\leq x<3[/tex]

or

[tex]2x-1=0[/tex] on [tex]3\leq x <6[/tex]

We now solve for [tex]x[/tex] on each interval,

[tex]x=-4,[/tex] on [tex]-4\leq x<3[/tex]

or

[tex]x=\frac{1}{2}[/tex] on [tex]3\leq x <6[/tex]

But observe that

[tex]x=\frac{1}{2}[/tex] does not belong to [tex]3\leq x <6[/tex]

This means it  can never be an intercept for this piece-wise function.

Hence our x-intercept is [tex](-4,0)[/tex]

3. Plotting the boundaries of the interval.

For [tex]f(x)=x+4[/tex] on  [tex]-4\leq x<3[/tex]

[tex]f(-4)=-4+4[/tex]

[tex]\Rightarrow f(-4)=0[/tex].

This point [tex](-4,0)[/tex] coincides with the x-intercept.

[tex]f(3)=3+4[/tex]

[tex]f(3)=7[/tex]

So we have the point [tex](3,7)[/tex]. But note that [tex]x=3[/tex] does not belong to this interval so we plot this point as a hole.

For [tex]f(x)=2x-1[/tex] on [tex]3\leq x <6[/tex]

[tex]f(3)=2(3)-1[/tex]

[tex]\Rightarrow f(3)=5[/tex]

So we plot [tex](3,5)[/tex]

[tex]f(6)=2(6)-1[/tex]

[tex]\Rightarrow f(6)=11[/tex]

So we plot [tex](6,11)[/tex] also as a hole.

Plotting all these points we can now graph the function,

[tex]f(x)=\left \{ {{x+4\:\:if\:\:-4\leq x<3}  \atop {2x-1\:\:if\:\:3\leq x<6}} \right.[/tex]

See attachment for graph.
Ver imagen kudzordzifrancis
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