0 is in the hundredths place
1 is in the hundreds place
4 is in the ones place
3 is in the tenths place
6 is in the tens place
9 is in the hundred-thousands place
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
F(-1) = 2(-1)^2 + 8(-1)
= 2(1) + (-8)
= -6
C is the answer to this question
