Answer:
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
Answer:
x = 31, x = 19
Step-by-step explanation:

Answer:
change the equation into one variable.
2 y equals 10 + x
y equals 5 + x by 2
now put that into the second equation
-3x + b parentheses 5 + x / 2 equals 11
-3x+b(5+ x/2)
-3x + b5 + bx/2 = 11
Answer: 32 feet
Step-by-step explanation:
Since 1 inch equals 8 feet and the parking lot has a width of 4 inches we multiply 8 times 4 giving you an answer of 32, so the parking lot's width is 32 feet.