Answer:
-0.375
Step-by-step explanation:
Way one(the harder one):
Let the line which passes through (1,4) and (9,1) be f(x)=kx+b
Sub (1,4) and (9,1) in and we get [tex]\left \{ {{4=1k+b} \atop {1=9k+b}} \right.[/tex]
=> (9k+b)-(k+b)=1-4
8k=-3
k=-3/8 or -0.375
Therefore the slope of the line is -3/8 or -0.375
Way two(the easier one):
k= [tex]\frac{change in y}{change in x}[/tex] = [tex]\frac{1-4}{9-1}[/tex] = -[tex]\frac{3}{8}[/tex]
