Answer list is a) 20√7 b)x(20√x+3) c)6√x^5/x^2 d)x^3(6√x^5 I want some help with this as well
Answer:
the second answer Is the right one
4x -3y + z = -10...............(1)
2x +y + 3z = 0...............(2)
-x +2y - 5z = 17...............(3)
First we multiply 3*(2) and add it to (1)
6x +3y +9z =0..................+(1)..................> 10x + 10z = -10......(4)
Then we multiply -2*(2) and add it to (3)
-4x -2y -6z =0 ...................+(3)................> -5x -11z = 17...........(5)
Multiply 2*(5) and add it to (4)
-10x -22z = 34...................+(4).................> -12 z = 24 ..............>>> z = -2
Substitute z in (4)............> 10x +10(-2) = -10.............................>>> x = 1
Substitute x and z in (2).....> 2(1) +y + 3(-2) = 0..................>>> y = 4
Solution (x,y,z) = (1,4,-2)
<h3>
Answer: 14 km per hour</h3>
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Work Shown:
x = rowing speed when there is no current
c = speed of the current
speeds are in km per hour
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Going downstream, i.e. with the current:
x+c = faster speed since the current is pushing you
distance = rate*time
d = r*t
40 = (x+c)*2
x+c = 40/2
x+c = 20
c = 20-x
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Going upstream, i.e. against the current:
x-c = slower speed since the current is working against you
d = r*t
16 = (x-c)*2
16 = 2x-2c
2x-2c = 16
2(x-c) = 16
x-c = 16/2
x-c = 8
x-(20-x) = 8 ... plug in c = 20-x
x-20+x = 8
2x-20 = 8
2x = 8+20
2x = 28
x = 28/2
x = 14 km per hour is the rowing speed when there is no current
Side note: the speed of the current is c = 20-x = 20-14 = 6 km per hour.
ANSWER
EXPLANATION
The given expression is
We multiply out to obtain,
Recall that,
We apply this rule to obtain,
This simplifies to
