Answer: the speed of the current is 9 mph.
Step-by-step explanation:
Let x represent the speed of the current.
A boat can travel 21 mph in still water. If it travels 270 miles with the current. It means that the total speed with which the boat travelled with the current is (21 + x) mph.
Time = distance/speed
Time spent by the boat in travelling 270 miles is
270/(21 + x)
In the same length of time, it travels 108 miles against the current. It means that the total speed with which the boat travelled against the current is (21 - x) mph.
Time = distance/speed
Time spent by the boat in travelling 108 miles is
108/(21 - x)
Since the time is the same, then
270/(21 + x) = 108/(21 - x)
270(21 - x) = 108(21 + x)
5670 - 270x = 2268 - 108x
108x + 270x = 5670 - 2268
378x = 3402
x = 3402/378
x = 9
Answer:
-3x + 6
Step-by-step explanation:
-3(x - 2) to find the equivalent of this expression, we need to multiply inside the parenthesis with -3 (with both x and -2)
-3(x - 2 = -3x + 6 (two negative expressions multiplied results in positive)
Two lines are perpendicular if and only if the product of their slopes is - 1.
So, you just need to find the slope of each line and find out the product of their slopes.
I will do one example for you.
L1: y = 3x + 5
L2: y = - 3x + 14
L3: y = -x/3 + 14
The slope of a line is the coefficient of the x.
So the slopes are:
L1: slope 3
L2: slope -3
L3: slope -1/3
So now multiply the slopes of each pair of lines:
L1 and L2: 3 * (-3) = - 9 => No, they are not perpendicular
L2 and L3: (-3) * (-1/3) = 1 => No, they are not perpendicular
L1 and L3: (3) * (-1/3) = -1 => Yes, they are penpendicular.
Angle 1 is equal to 48°
if angle 3 and 2 are known you add them and subtract from 180
Answer: x=1, y=-2
Step-by-step explanation:
System
y=3x-5
y=x-3
3x-5=x-3
3x-x=-3+5
2x=2
x=2:2=1
y=x-3=1-3=-2
