Question 864461
D=0.04V^2 + 0.8V
285=0.04V^2+0.8V
0.04V^2+0.8V-285=0 MULTIPLY BY 100
(4V^2+80V-28,500=0
(V-75)(V+95)=0
V-75=0
V=75 MPH. ANS.