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Please help! Which direction would the graph y= Ix-4I+3 open? a) left b) up c) right d) down

User Latrell
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2 Answers

3 votes
The answer should be c
User Dennis Lyubyvy
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7 votes
The graph of y=|x-4|+3 and the graph of y=|x-4| open the same direction,

because y=|x-4|+3 is y=|x-4| shifted 3 units up, entirely. So if one opens upwards, the other does so as well.



So consider the graph of y=|x-4|. This graph is the graph of y=|x| shifted 4 units right.

To show this, in the function y=|x|, consider the points (-2, 2) (because for x=-2, y=|x|=|-2|=2)

and point (2, 2).

Now consider y=|x-4|, if y = 2, then

i) x-4 = 2, which means x=6 OR
ii) x-4 =-2, which means that x=2

So we have the points (2,2) and (6, 2)

the value 2 was taken at -2 and 2 in y=|x|

the value 2 is taken at x=2 and x=6 in y=|x-4|


this proves that the graph of y=|x-4| is the graph of y=|x| shifted 4 units right.



This means that both graphs open the same way.



Thus consider the graph of y=|x|,

i) for x=0, y=0,

ii) for x>0, for larger values of x, we have larger values of y,

for example: 5>3, and |5|>3, so the graph increases

iii) for x<0, for smaller values of x, we have larger values of y

for example: -5<-3, |-5|=5>3=|-3|, thus the graph is decreasing as we move right, up to 0, then it starts increasing.


All these mean that the graph of y=|x| opens upwards, so the graph of y=|x-4|+2 also opens upwards.


Answer: b
User Sameer Vartak
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6.5k points
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