30x-12-8x+40
22x-12+40
22x +28
Answer:
- boat: 15 mph
- current: 5 mph
Step-by-step explanation:
The relation between time, speed, and distance is ...
speed = distance/time
__
The speed downstream is ...
downstream speed = (100 mi)/(5 h) = 20 mi/h
The speed upstream is ...
upstream speed = (100 mi)/(10 h) = 10 mi/h
The boat's speed in still water is the average of these:
boat speed = ((downstream speed) + (upstream speed))/2 = (20 +10)/2 mi/h
boat speed = 15 mi/h
__
The speed of the current is the difference between the travel speed and the boat speed:
current speed = downstream speed - boat speed
= (20 mi/h) - (15 mi/h)
current speed = 5 mi/h
Answer:
f(8) = -9
Step-by-step explanation:
Substitute 8 in for x.
f(8) = -2(8) + 7
f(8) = -16 + 7
f(8) = -9
When a variable is eliminated and the resulting equation is always true, the equation represents a quantity independent of the eliminated variable.
Answer:
Hope this helps you.
The answer is 61, x+40+5x+14=180, so x equals 21. 5(21)+14 ends up equaling 119, so 180-119 equals 1