Which of the following describes the non-rigid transformation in the function shown below?
y-1=-(3x+1)^2

A. The graph is shifted 3 units down.
B. The graph is stretched vertically by a factor of 3.
C. The graph is reflected across the x-axis.
D. The graph is stretched horizontally to 1/3 the original width.

Question

Which of the following describes the non-rigid transformation in the function shown below?
y-1=-(3x+1)^2

A. The graph is shifted 3 units down.
B. The graph is stretched vertically by a factor of 3.
C. The graph is reflected across the x-axis.
D. The graph is stretched horizontally to 1/3 the original width.

anonymous · Answer

The first question you need to ask yourself is what is the basic function? As in the type of function you're working with.

anonymous · Answer

would it be point-slope?

anonymous · Answer

try to get it to slope intercept form  y=mx+b

anonymous · Answer

@ali1029  you there O.O

anonymous · Answer

how would i do that?

anonymous · Answer

y-1=-(3x+1)^2
y-1=-3x-1^2
y-1=-3x1
y=-3x+2

anonymous · Answer

No I was more referring to the fact that we are dealing with a quadratic function. As in y(x)=ax^2.

anonymous · Answer

ohhh you should listed to him he seems better at this than me

anonymous · Answer

Solving for y yields:$$y=-(3x+1)^{2}+1$$Factoring out the 3:$$y=-(3(x+\frac{ 1 }{ 3 }))^{2}+1$$
From this we can see that the base function y(x)=x^2 has been:
1)stretched vertically by a factor of 3: y(3x)=(3x)^2
2)shifted left 1/3 units: y(x+1/3)=(3(x+1/3))^2
3)flipped across the y axis: -y(x)=-(3(x+1/3))^2
4)shifted down 1 unit y(x)-1=-(3(x+1/3))^2
which is what we started out with.

anonymous · Answer

I hope that isn't too confusing. I'm trying to show how this is really just taking steps and building up the function based on the changes you want to make to the base function.

anonymous · Answer

im still trying to understand this, sorry

anonymous · Answer

would the answer be B? because it is going up higher and vertically?

anonymous · Answer

Give me your number and, I'll text you the answer.

anonymous · Answer

Creepy

anonymous · Answer

Just one second. I'm making sure I didn't switch the terminology for the stretching part.

anonymous · Answer

Get out @naevusx . That is really creepy.

anonymous · Answer

& okay

anonymous · Answer

Actually the step "1)stretched vertically by a factor of 3: y(3x)=(3x)^2" should be shrunk horizontally by a factor of 1/3.

anonymous · Answer

It's because you're causing the function to reach y values 3 times as fast so it kind of compresses the x axis if that makes sense.

anonymous · Answer

oh okay, i see what you're saying

anonymous · Answer

|dw:1379721895814:dw| kind of like this