Question

6. Describe why the following answer is incorrect and what the correct answer should be?

Write an equation in slope-intercept form whit the given information.
Goes through the points (1, -2) and (3, 6)

Answer 1

The equation in slope-intercept form is:

• y=4x-6

Explanation:

Given the points

• (1, -2)

• (3, 6)

Finding the slope

`\mathrm{Slope}=(y_2-y_1)/(x_2-x_1)`

`\left(x_1,\:y_1\right)=\left(1,\:-2\right),\:\left(x_2,\:y_2\right)=\left(3,\:6\right)`

m = (6-(-2)/(3-1) = 8/2 = 4

Thus, the slope is m = 4

MISTAKE AND CORRECTION

NOTE: HERE THE PERSON MADE A MISTAKE.

• Because, his slope m=2, which is incorrect.

• Thus, the person found the slope incorrectly.

The correct slope = m = 4

The slope-intercept form is

y=mx+b

Plug in (3, 6) and m=4 to find b

6 = 4·3 + b

6 = 12+b

6-12 = b

-6 = b

Plug in m=4 and b=-6 in the slope-intercept form

y=mx+b

y=4x+(-6)

y=4x-6

Thus, the equation in slope-intercept form is:

• y=4x-6