# How do you find the slope that is perpendicular to the line 8x+9y=7?

The slope of the perpendicular line is $\frac{9}{8}$
The slope of the line $8 x + 9 y = 7 \mathmr{and} 9 y = - 8 x + 7 \mathmr{and} y = - \frac{8}{9} x + \frac{7}{9}$ is ${m}_{1} = - \frac{8}{9}$ . [Compare with straight line equation $y = m x + c$]
The product of slopes of two perpendicular lines is ${m}_{1} \cdot {m}_{2} = - 1 \therefore {m}_{2} = - \frac{1}{m} _ 1 \therefore {m}_{2} = - \frac{1}{- \frac{8}{9}} = \frac{9}{8}$
The slope of the line perpendicular to the line $8 x + 9 y = 7$ is $\frac{9}{8}$[Ans]