Answer:
y = -x +6
Explanation:
i honestly didn't know what form you wanted so i put it in slope-intercept form for you :D
formula for slop-intercept form:
y=mx+b
12 = -1 ( -6 ) + b -----> filled in the m, x and y
12 = 6 + b -----> do PEMDAS
12 - 6 = b -----> moved 6 to the other side to isolate variable
6 = b -----> you found the y-intercept
y = -x + 6 ------> fill the equation in :D