3x=21

Divide each term in 3x=21 by 3.

3×3=213

Cancel the common factor of 3.

Cancel the common factor.

3×3=213

Divide x by 1.

x=213

x=213

Divide 21 by 3.

x=7

x=7

Since x=7 is a vertical line, there is no y-intercept and the slope is undefined.

Slope: Undefined

y-intercept: No y-intercept

Graph 3x=21