Respuesta :

To get the slope of this function, let's rewrite in the slope-intercept form.

The slope-intercept form have the following form:

[tex]y=mx+b_{}[/tex]

where 'm' represents the slope and 'b' represents the y-intercept.

We have the following function

[tex]7x+3y=21[/tex]

To rewrite in the slope-intercept form, we start with our original equation

[tex]7x+3y=21[/tex]

Then, we can subtract '7x' from both sides:

[tex]\begin{gathered} 7x+3y=21 \\ 7x+3y-7x=21-7x \\ 3y=21-7x \end{gathered}[/tex]

And then, finally, divide both sides by 3.

[tex]\begin{gathered} 3y=21-7x \\ \frac{3y}{3}=\frac{21-7x}{3} \\ y=\frac{21}{3}-\frac{7x}{3} \\ y=7-\frac{7x}{3} \end{gathered}[/tex]

And with this, we have our final equation

[tex]y=7-\frac{7}{3}x\Leftrightarrow y=-\frac{7}{3}x+7[/tex]

Done! If you compare this last equation with the general form of the line, you're going to find:

[tex]\begin{cases}m=-\frac{7}{3} \\ b=7\end{cases}[/tex]

Where 'm' is the slope, and 'b' the y-intercept.