8x - 9y + 2 = 0 -9y = -8x - 2 y = 8/9x + 2/9.....the slope here is 8/9. A perpendicular line will have a negative reciprocal slope. All that means is " flip " the slope and change the sign. So our perpendicular line will need a slope of -9/8 (see how I flipped the slope and changed the sign)
y = mx + b slope(m) = -9/8 (-7,-9)...x = -7 and y = -9 now we sub and find b, the y int -9 = (-9/8)(-7) + b -9 = 63/8 + b -9 - 63/8 = b -72/8 - 63/8 = b -135/8 = b
so ur perpendicular equation is : y = -9/8x - 135/8
