The first, third, and fourth choices are functions. A relation is a function when x does not repeat. For the second choice, -4 repeats. Therefore, it is not a function. The other choices do not repeat an x-coordinate, so they are correct.
Answer:

Step-by-step explanation:
So we have the expression:

Distribute the negative:

Combine like terms:

And we're done!
Answer:
)x + 5)(x - 5)
Step-by-step explanation:
x² - 25 ← is a difference of squares and factors in general as
a² - b² = (a + b)(a - b), thus
x² - 25 = x² - 5² = (x + 5)(x - 5)
Answer:
x = <u>12/5</u>
Step-by-step explanation:
Since the original is 10 and the second is 6, that means that the scale is 10:6 or 5:3. It can also be related as %60 of the length.
<u>Step 1: Make an equation</u>
10/6 = 4/x
<u>Step 2: Cross Multiply</u>
10x = 24
<u>Step 3: Divide</u>
10x / 10 = 24 / 10
24/10 = 12/5
x = 2.4