Answer:
-5/2
Step-by-step explanation:
for perpendicularity;
[tex]m1 = \frac{ - 1}{m2} [/tex]
where m1 is first slope
and m2 is second slope
so here, let m1 be green line slope
and m2 be red line slope
thus,
[tex]m2 = \frac{ - 1}{m1} [/tex]
[tex]m2 = \frac{ - 1}{ \frac{2}{5} } = - 1 \div \frac{2}{5} [/tex]
[tex] = - 1 \times \frac{5}{2} = \frac{ - 5}{2} [/tex]
