To write the equation of a line that passes through points (1,1) and (3,5), answer the following questions to guide your thought process:

A) Given points (x_{1}, y_{2}) and (x_{2} - y_{2}) what is the equation for slope?

m =

S

Y_{2}

x_{1}

y_{1}

x_{2}

B) What is the slope of a linear function containing the points (1, 1) and (3, 5) ?

m =

Top part

5

1

Bottom part

3

1

m=

4

2

m=

2

C) When the two points from part b are graphed, and a line is drawn through the points. Which graph on the right shows the correct result?

The graph that shows a line crossing through points (1.1) and (3,5) is graph
The answers is A

D) Based on the previous steps (A, B, and C), fill in the missing variables in the slope-intercept form, y = mx + b to write the equation of the line passing through the points (1,1) and (3,5).

y= *blank 1* x + *blank 2*

Another way to write the equation

is *blank 3*

Options for blanks 1 and 2

A 1/2
B -1/2
C -2
D 2

Options for blank 3

y = (1/2) * x - 1

y = - 2x - 1

A y = 2x - 1

B y = (1/2) * x - 1/2

C y = 2x - 1/2

D y = - 2x - 1/2

1 answer

Let's go through the questions step by step to find the answers:

A) The formula for the slope \( m \) between two points \((x_1, y_1)\) and \((x_2, y_2)\) is:

\[ m = \frac{y_2 - y_1}{x_2 - x_1} \]

B) Now we will use this formula to find the slope of the line containing the points \((1, 1)\) and \((3, 5)\):

  • Here, \( (x_1, y_1) = (1, 1) \) and \( (x_2, y_2) = (3, 5) \).
  • Substituting into the slope formula:

\[ m = \frac{5 - 1}{3 - 1} = \frac{4}{2} = 2 \]

So, the slope \( m = 2 \).

C) The line connecting the points \( (1, 1) \) and \( (3, 5) \) with a slope of 2 would rise 2 units for every 1 unit it moves to the right. When this graph is drawn, it will clearly pass through these points. As for the specific graphs, you would need to refer to the graphs provided, but the one that crosses through \( (1, 1) \) and \( (3, 5) \) is the correct option.

D) Now, to write the equation of the line in slope-intercept form \( y = mx + b \):

  1. We already found that \( m = 2 \).
  2. Next, we need to find \( b \), the y-intercept. We can do this by substituting one of the points into the equation.

Using the point \( (1, 1) \):

\[ 1 = 2(1) + b \implies 1 = 2 + b \implies b = 1 - 2 = -1 \]

Thus, the slope-intercept form of the line is:

\[ y = 2x - 1 \]

In terms of the blanks provided:

  • Blank 1 would be 2 (for the slope \( m \)).
  • Blank 2 would be -1 (for the y-intercept \( b \)).
  • Blank 3 would be y = 2x - 1 (the final equation).

So the final answers are:

  • Blank 1: 2
  • Blank 2: -1
  • Blank 3: y = 2x - 1