Let the speed of plane in still air be x and that wind be y
therefore:
x+y=490
x-y=390
next we solve for the values of x and y, first we add the above equations. This will give us:
2x=880
x=880/2
x=440 miles per hour.
substituting the value of x in one of the equations and solving for y we get:
440+y=490
y=490-440
y=50 miles per hour
I believe the correct answer is B. -5
Answer:
x= (y+2)/5
Step-by-step explanation:
Let f(x) = y
y = 5x -2
Adding 2 on both sides
y +2= 5x
Divinding by 5 in both sides
(y+2)/5 = x = f*(x)
Therefore,
f*() = (y+2)/5
.
Hope this helps you...
