Draw points J and K in the coordinate axis, and join them so that the top of the vector is point K.
the magnitude of the vector is just the length of the segment JK, so we can either write it as |JK| or |KJ|, it does not make any change.
Let O be the point in the x axis such that KO is perpendicular to OJ, as shown in the picture.
From the Pythagorean theorem:

units
since |OK|=|OJ|, the right triangle KOJ is isosceles, so the measure of KJO is 45°, which means that the angle of vector JK to the positive x axis is 180°-45°=135°
Answer: magnitude=

units, direction : 135°
A parallel line has the same slope so it'd still be 2x with any random number so y=2x+5
Let
x = velocity of the water current
t1 = time taken to go downstream
t2 = time taken to go upstream
t1 + t2 = 8
t2 = 8 – t1
v = D/t
Downstream
(4 + x) = 6/ t1
t1 = 6/(4+x)
Upstream
(4 – x) = 6/t2
Substitute expression for t2 to obtain
(4 – x) = 6/ (8-t1)
Substituting the expression of t1 to make a single variable equation, obtaining
6 = (4-x)*(8 – 6/(4+x))
Solving for x,
x= 3.16 m/s
Answer:
7.125*10⁻⁹ = 0.000000007125
Step-by-step explanation:
7.125*10⁻⁹ = 0.000000007125