Think about it.... the y-axis intercept occurs at the y-axis...this is where x = 0 put in x = 0
NOTE 'x-intercept' is a shorthand method of saying 'x-axis intercept'
6(0) + 2y = 18 y = 9 = y-axis intercept
the x-axis intercept occurs when y = 0
6x + 2(0) = 18 x = 3 = x - axis intercept