Question 201412
(-3, -2); perpendicular to 
-7x + 9y = -42
9Y=7X-42
Y=7X/9-42/9 THIS LINE HAS A SLOPE=7/9 (RED LINE)
A PERPENDICULAR LINE TO THIS LINE HAS A SLOPE=-9/7
Y=mX+b
-2=-9/7*-3+b
-2=27/7+b
b=-2-27/7
b=(-2*7-27)/7
b=(-14-27)/7
b=-41/7 THIS IS THE Y INTERCEPT.
y=-9x/7-41/7 (GREEN LINE)
{{{ graph( 300, 200, -6, 5, -10, 10, 7x/9 -42/9,-9x/7 -41/7 ) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions 7x/9 -42/9 and -9x/7 -41/7).