I am a little confused with this one and I have a test tomorrow

Why does y = -3x -3 (slope-intercept form) become 3x + y + 3 = 0 in standard form instead of -3x-y-3 = 0?

and - 3 = y-(-10)/x-1 should be - 3x-y-7 = 0 so why is it 3x+y+7 = 0?

Mind explaining? Thanks so much!