Given y = -x + 4, determine the output value (y) when the input value is 9.

The output value is $\boxed{-5}$.

8.2.

The values are $a = \boxed{9}$ and $b = \boxed{11}$.

8.3.

Inputs: 2, 3, 8, 10
Outputs: 16, 22, 52, 64

Using the first two pairs (2, 16) and (3, 22):
For (2, 16): $16 = 2m + c$ (Equation 1)
For (3, 22): $22 = 3m + c$ (Equation 2)

The rule is $y = 6x + 4$.
Check for $x=8$: $y = 6(8) + 4 = 48 + 4 = 52$ (Matches)
Check for $x=10$: $y = 6(10) + 4 = 60 + 4 = 64$ (Matches)
The rule is $\boxed{y = 6x + 4}$.

QUESTION 9 [ALGEBRAIC EXPRESSIONS]

9.1. Given the expression: $x^2 - 6x - 8$

9.1.1.

Terms are separated by addition or subtraction signs.
The terms are $x^2$, $-6x$, and $-8$.
There are $\boxed{3}$ terms in the expression.

9.1.2.

This is $-6x$.

The coefficient of $x$ is $\boxed{-6}$.

9.1.3.

The constant term is $\boxed{-8}$.

9.1.4.

For $x^2$, the power is 2.
For $-6x$, the power is 1 (since $x = x^1$).
For $-8$, the power is 0 (since $x^0 = 1$).

The highest power is 2.
The degree of the expression is $\boxed{2}$.

9.1.5.

The value of the expression if $x = -3$ is $\boxed{19}$.