Step-by-step explanation:
all real numbers not equal to 0
all real numbers
Answer:
equation 2into minus 3 into equation 1
8x+ 3y= -28
-3x-3y=18
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5x=10
x =2
put value of y in equation 2
8 into 2+3y=-28
16+3y= -28
3y= -28+16
3y= -12
y= -4
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
<span>20 hundreds is equal to 2 thousands, however 20 hundreths is not equal to 2 thousandths. 2 in the 0,2 is 100 times greater than 2 in 0,002.
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