Determine the slope and y-intercept of the graph: 3x + y = 8.I found the y-intercept but i can't find the slope.

3 Answers

hala718's profile pic

hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted on

Given the equation of the line:

3x + y= 8

==> y= 8-3x

We need to find the slope and the y-intercept.

The slope if the factor of x when the equation is written in the slope-form y=mx + b ==> Then the slope is m.

==> Then, in your question the slope is m= -3

The y-intercept is the point such that the line intersects with the y-axis. Then, the value of x is 0.

We will substitute with x=0 and determine y-coordinate.

==> y= 8-3x = 8-3(0)= 8

Then y-intercept is the point (0,8).


tazeen's profile pic

tazeen | Student, Grade 10 | (Level 1) eNoter

Posted on

3x + y= 8

=y= 8-3x as y=mx+c where m is the slope

Now m=-3

Now x=0 since zero on the x-axis is the y-axis

= y= 8-3x = 8-3(0)= 8

Then y-intercept is the point (0,8). [ans]


lochana2500's profile pic

lochana2500 | Student, Undergraduate | (Level 1) Valedictorian

Posted on

3x + y = 8

Rewrite the equation as y =mx+c type

y = -3x + 8

therefore slope of the line = (-3)

y-intercept is the point (0,8)