Answer:
[tex]-\frac{2}{5}.[/tex]
Step-by-step explanation:
1) if to re-write the given equation into slope-interception form, then:
[tex]y=\frac{5}{2}x-7;[/tex]
the slope of the given line is 5/2;
2) according to the rule of perpendicular, the required slope should be:
s*(5/2)=-1;
3) if to solve this equation (s*5/2=-1), then s=-2/5 or -0.4.
