Well, a linear function is proportional, a straight line (on a graph). And the numbers must not have the same answer. For instance, if the X input is 5, and the Y output is 7. And then another X input is 5, and the Y output is 8, that's non-linear.
So, the Answer would be the third graph. This is because the X values are steadily increasing, and so are the Y values.
For the X and Y values, for each time X increases by 1, Y increases by -8. This is, linear because both sides are constantly and evenly increasing.
The domain is (-infinity, 6] I believe.
There can be no negative in a sqrt
so x+1 must be equal or greater then 0
x+1

0
x

-1
so all answers must be greater then or equal to -1
-1,0,1,2,3,4,5,6,7,8
(-1,infinity) is the domain
It would be (2,1)
y=-2*2+5
y=-4+5
y=1
<u> Equation:</u>
x(x - 5) + 3(x + 5)
<u>Steps:</u>
x(x - 5) + 3(x + 5)
<u>Expand:</u>
x(x - 5 ): x^2 - 5x
x^2 - 5x + 3(x + 5)
<u>Expand:</u>
3(x + 5): 3x + 15
x^2 - 5x + 3x + 15
<u>Add Similar Elements: </u>
-5x + 3x
= -2x
Answer x^2 - 2x + 15 Doesn't Factor
Hope that helps!!! : )