An airplane takes 3 hours to travel a distance of 1680 miles with the wind. The return trip was 4 hours against wind. Find the speed of the plane in still air and the speed of the wind

Speed of plane in still air: 490  mile/hour

speed of wind: 70  mile/hour

Step-by-step explanation:

still speed = x        wind speed = w

with wind: speed = still + wind

(x+w) * 3 = 1680     ...a

against wind: speed = still - wind

(x-w) * 4 = 1680    ...b

b-a ... 4x-4w-3x-3w = 0

x-7w = 0

x = 7w

substitution: (7w+w)*3 = 1680      8w = 560       wind speed (w) = 70

still speed (x) = 7w = 490 mile/hour

y=mx+b

step-by-step explanation:

m slope

b y-intercept

option 2 is correct.

step-by-step explanation:

we are given two inequality equation

x+y> 5 and -3x+2y< -2

first we draw the graph of both function using t-table method

equation: x+y> 5

for x=0, y=5

for x=-5, y=0

table:

x   :   0     5

y   :   5     0

test point (0,0) , 0> 5

false

equation: -3x+2y< -2

for x=0, y=-1

for x=2, y=4

table:

x   :   0     2

y   : -1       4

test point (0,0) , 0< -2

true

now we draw the graph. see the attachment for graph.

common region would be solution set.

option 2 is correct.