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
Answer:
A. 
B. 
C. 
Step-by-step explanation:
A. . Any number could work as long as the coefficients for x and y stays the same. You are basically imposing that the quantity 2x-4y (if you bring 4y to the LHS) is equal to both -3 AND 
, or any number you like. But yesterday was 3/14 so let's pick a fun number!
B. Or 
. Or as long as you don't pick the same ratios of x and y you're golden. But x=1 is the easiest that comes to mind
C. . To get infinitely many solutions you just have to rewrite the equation again. Maybe move things around if you prefer, or multiply everything by a number you lile.
Answer:
The answer is obviously letter A!
Answer:
9
Step-by-step explanation:
X+y=2(x-y)
x+y=2x-2y
3y=x
x-2y=2
then,substitute
(3y)-2y=2
y=2
so,x=3(2)
x=6
x the largest
y the smallest
