How do you find the x intercept of an equation?

To find the x intercept of an equation, simply plug in 0 for the y value, and solve for x (at the point where the line crosses the x axis, y will be equal to 0).

Ex/

2y + 3x = 21
3x = -2y + 21 (move y to opposite side)
3x = -2(0) + 21 (plug in 0 for y)
3x = 0 + 21 (multiply)
3x = 21 (add 0 and 21)
x = 7 (divide both sides by 3 to be left with only an x)

For this line, the point where the line intercepts the x axis is (7,0).