Answer: m=-1/2, b=3
Step by step explanation:
X+2y=6    - rewrite the equation in slope-intercept form
Y=-1/2x+3    - since the equation is written in slope-intercept form, y=Mx+b, identify the slope of the lines as the coefficient next to the variable 
Y=-1/2x+3, m=-1/2    - identify the y-intercept of the line as the constant term 
Y=-1/2x+3, m=-1/2, b=3   - the slope of the line is m=-1/2 and the y-intercept is b=3
M=-1/2, b=3