write in equation in slope intercept form for the line perpendicular to y=-3x+9 that passes through the line 9,9

y = 3x - 18

Step-by-step explanation:

The given line, y = - 3x + 9, has slope - 3. Any new line perpendicular to this has slope + 3/1, or just 3.

Start with the general slope-intercept form of the equation of a straight line:

y = mx + b. Now substitute 9 for y, 9 for x and 3 for m:

9 = 3 (9) + b. Then b = - 18, and the desired equation is y = 3x - 18.