I need help with Graphing Square Root Functions. Please anyone help.
1. What is the domain of the function \[y=3\sqrt{6x+42}\]
do you know that you can not take the square root of a number and get are real answer unless the number is positive or zero?
The choices are A. x ≥ 0 B. x ≤ 7 C. x ≥ –6 D. x ≥ –7
Yes I know that.
I think that answer is D.
But I was confused because I thought you had to flip the equal to or greater than sign when you divide.
so set up an inequality that mean the terms inside the square root are equal to or greater than zero
you only have to flip the inequality sign when you are dividing by a negative
\[6x+42\ge0\]
thats it ...
\[6x \ge-42\]Subtract 42 get
Divide by 6 and get\[x \le-6\]
Oops I mean\[x \le -7\]
\[42=6\times7\]
Because when you divide you flip the sign, right?
Yes but the 42 is negative.
you dont have to flip the sign in the question, because you were dividing by positive 6
So is it D. and your not supposed to flip the sign?
in this*
Oh....Ok
So it is D.
I thought so.
Not to waste more of you time but that one I had already knew the answer I just wanted to figure out why I kept flipping the sign. So could you help me out with 2 more and then I'm done?
we can check \[y=3\sqrt{6(-7)+42}=3\sqrt0, \]
Ok cool
Yes, more
2. What are the domain and range of the function \[y=2\sqrt{3x+4}-5\]? (1 point) 3. When will the dependent variable in the equation equal or exceed 4? (1 point)x ≥ –0.17 x ≥ 45 x ≥ 48 x ≥ 53
so, can you set up the inequality like before?
No because I didn't know what to do with the 5...
Because it is out of the sqrt.
the only restricted terms are either in radicals, denominators or some other strange places,
so just look at the terms under the square root here
Ok so could you set it up fo r me so I learn?
\[3x+4-5\ge0\]
Is that it?
if the 5 isn't in the square root \[y=2\sqrt{(3x+4)}-5\] then it wont effect the domain \[3x+4≥0\]
Ok
so 4 divided by 3?
Thats 1.3 repeating.
\[3x+4≥0\]take away four from both sides\[3x+4-4≥0-4\]divide by three
Oh you leave it at \[\frac{ 4 }{ 3 }\]
-4/3
yeah but it should be -4/3
yeah
so you have \(x≥-\tfrac43\)
so is it \[x \ge -\frac{ 4 }{ 3 };y \ge-5\]
Is that right?
\[\color{red}\checkmark\]
\[x \le -\frac{ 4 }{ 3 };y \le-5\]Or would it be
well when you look at \[y=2\sqrt{(3x+4)}-5\] there are two main term the term with the square root can only work if it equals zero or greater
When will the dependent variable in the equation \[y=\sqrt{x+4}-3\] equal or exceed 4? x ≥ –0.17 x ≥ 45 x ≥ 48 x ≥ 53
Ok last one.
do you remember if the dependent variable is x or y?
The last three choices, when I plug them in, all range from 4 to 4.56968 or somthing like that.
It would be y because that is the outcome.
so when \(y≥4\) \[\quad\sqrt{x+4}-3≥4\]
So is it B.?
add three to both sides then square both side, the take away four from both sides
you add 3 and thats \[\sqrt{x+4}\ge\]
ok
what happened to RHS?
i forgot to put 3 on the other side
i forgot to put 3 on the other side
so it 3-4 squared? so its A.
Right?
i got 1 when i did (3-4)^2
um wait
Ok so what did you get?
\[\quad\sqrt{x+4}-3≥4\]add three to both sides \[\quad\sqrt{x+4}-3+3≥4+3\]then, square both sides, \[\quad(\sqrt{x+4}-3+3)^2≥(4+3)^2\] the take away four from both sides \[\quad(\sqrt{x+4}-3+3)^2-4≥(4+3)^2-4\]
Ok now to simplify
ok its 45
\[x≥\]
I was right when I said b
yes
Thanks fo rall of you help.
1. What is the domain of the function ? (1 point) (0 pts) x ≥ 0 (0 pts) x ≤ 7 (0 pts) x ≥ –6 (1 pt) x ≥ –7 1 /1 point 2. What are the domain and range of the function ? (1 point) (1 pt) (0 pts) (0 pts) (0 pts) 1 /1 point 3. When will the dependent variable in the equation equal or exceed 4? (1 point) (0 pts) x ≥ –0.17 (1 pt) x ≥ 45 (0 pts) x ≥ 48 (0 pts) x ≥ 53 1 /1 point 4. Which function is shown on the graph below? (1 point) (0 pts) (0 pts) (1 pt) (0 pts) 1 /1 point Note: The below question was entered in error. You will receive credit for ANY answer. 5. The function models the time (t) in seconds that an object has been falling after the object has fallen d feet. When will the time be more than 1 minute? (1 point) (1 pt) d ≥ 16 ft (1 pt) d ≥ 225 ft (1 pt) d ≥ 3,600 ft (1 pt) d ≥ 57,600 ft 1 /1 point The final score is 5/5 (100%).
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\[5/5=100\%\quad\color{red}{\checkmark\checkmark\checkmark\checkmark\checkmark}\]
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