1. **Stating the problem:** We have a table of values for $x$ and $y$:
$$\begin{array}{c|ccccccc}
x & 1 & 2 & 3 & 4 & 5 & 6 & 7 \\
y & 5 & 7 & 9 & _ & _ & _ & 17 \\\end{array}$$
We need to:
- (ii) Determine the rule for the mapping from $x$ to $y$.
- (b) Plot the points for the ordered pairs $(x,y)$.
- (c) Find:
- (i) $y$ when $x=0$.
- (ii) $x$ when $y=14$.
2. **Determine the rule for the mapping:**
Look at the given $y$ values for $x=1,2,3$:
- When $x=1$, $y=5$
- When $x=2$, $y=7$
- When $x=3$, $y=9$
Notice the pattern: $y$ increases by 2 as $x$ increases by 1.
This suggests a linear rule of the form:
$$y = mx + c$$
where $m$ is the slope and $c$ is the $y$-intercept.
Calculate the slope $m$:
$$m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{7 - 5}{2 - 1} = \frac{2}{1} = 2$$
Use one point to find $c$:
$$5 = 2(1) + c \implies c = 5 - 2 = 3$$
So the rule is:
$$y = 2x + 3$$
3. **Find missing $y$ values for $x=4,5,6$:**
- For $x=4$:
$$y = 2(4) + 3 = 8 + 3 = 11$$
- For $x=5$:
$$y = 2(5) + 3 = 10 + 3 = 13$$
- For $x=6$:
$$y = 2(6) + 3 = 12 + 3 = 15$$
Check for $x=7$:
$$y = 2(7) + 3 = 14 + 3 = 17$$
which matches the given value.
4. **Plot the points:**
The ordered pairs are:
$$(1,5), (2,7), (3,9), (4,11), (5,13), (6,15), (7,17)$$
5. **Find $y$ when $x=0$:**
Using the rule:
$$y = 2(0) + 3 = 3$$
6. **Find $x$ when $y=14$:**
Set $y=14$ and solve for $x$:
$$14 = 2x + 3$$
$$2x = 14 - 3 = 11$$
$$x = \frac{11}{2} = 5.5$$
**Final answers:**
- Rule: $y = 2x + 3$
- Missing $y$ values: 11, 13, 15
- $y$ when $x=0$ is 3
- $x$ when $y=14$ is 5.5
Linear Mapping
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