Question

Write an equation for each linear function described. Show your work. The graph of the function passes through the point (2,1), and y increases by 4 when x increases by 1.

Answer 1

Step-by-step explanation:

As

• The graph of the function passes through the point (2,1), and

• y increases by 4 when x increases by 1.

so

x             y

2             1

3             5

4             9

5             13

6             17

and so on

From the table:

$\mathrm{Slope\:between\:two\:points}:\quad \mathrm{Slope}=\frac{y_2-y_1}{x_2-x_1}$

$\left(x_1,\:y_1\right)=\left(2,\:1\right),\:\left(x_2,\:y_2\right)=\left(3,\:5\right)$

$m=\frac{5-1}{3-2}$

$m=4$

As the slope-intercept form of the line is

$y=mx+b$

putting m=4 and any point, let say (2, 1) to find y-intercept 'b'.

$1=\left(4\right)2+b$

$8+b=1$

$8+b-8=1-8$

$b=-7$

So putting $b=-7$ and $m=4$  in the slope-intercept form of the line

$y=\left(4\right)x+\left(-7\right)$

$y=4x-7$

Therefore, the equation for the linear function will be:

$y=4x-7$