There is a rule:
One input(x-value) can only have one output(y-value) in order to be a function.
If one input has more than one output, it is not a function.
(This doesn't apply to outputs, one output can have more than one input and still be a function)
The 1st option is not a function because the inputs 9 and 10 have more than one output.
The 2nd option is not a function because the input 3 has more than one output.
The 3rd option is a function because each input only has one output.
The 4th option is not a function because the input 5 has more than one output.
<h2>Answer:</h2><h2>good to know</h2><h2 /><h2>thx :)</h2>
Answer:

Step-by-step explanation:
1) Use square sum: (a + b)² = a² + 2ab + b².

<u>Therefor</u><u>,</u><u> </u><u>the</u><u> </u><u>answer</u><u> </u><u>is</u><u> </u><u>x</u><u>²</u><u> </u><u>+</u><u> </u><u>2xy</u><u> </u><u>+</u><u> </u><u>y</u><u>²</u>.
9514 1404 393
Answer:
3 3/4
Step-by-step explanation:
Mandy needs 6 times 5/8 yards, or ...
6(5/8) = 30/8 = 3 6/8/ = 3 3/4 . . . yards
The answer is 12ft. Because if 1in is 3ft then 4in will be 4 multiplied by 3