If possible write the following equation in slope-intercept form.
$$3 x + 6 y + 24 = x - y$$

a) What is the value of $m$ when written in slope-intercept form? If the equation cannot be written in slope-intercept form, enter none in the box.
$m =$

b) What is the value of $b$ when written in slope-intercept form? If the equation cannot be written in slope-intercept form, enter none in the box. $b =$