Find the Y-Intercept
-3x + 7Y = 21

(0, 3)

Step-by-step explanation:

To find the y-intercept of a linear equation, we simply need to put the equation into "slope-intercept" form.  This will allow the y-intercept to be shown as the constant being added to the equation.  To put a linear equation into slope-intercept form, we simply need to solve for Y.  Let's do that.

-3x + 7Y = 21

3x + -3x + 7Y = 3x + 21

7Y = 3x = 21

(1 / 7) * 7Y = (3x + 21) * (1 / 7)

Y = (3x / 7) + (21 / 7)

Y = 3x/7 + 3

Now that we have the Y isolated, we can see the constant being added is 3.  Hence, the y-intercept is (0,3) since by definition the y-intercept is the point at which the line crosses the x axis (where x = 0).  If you plug x=0 into the equation, you get Y = 3.

Cheers.