<span> we know the length of the cable is 9m.
That means the magnitude of </span><span><span>r<span><span><span>AB</span></span><span></span></span></span>=9</span><span>m.
The unit vector, denoted u, is each of </span><span>r<span><span><span>AB</span></span><span></span></span></span><span> divided by the magnitude.
</span>u=<span>(<span><span>x/9</span><span></span></span>i−<span>y/9<span></span></span>j−<span>z/9<span></span></span>k<span>)
</span></span><span>We can also figure out the unit vector of F.
</span>u=(350i - 250j - 450k)/√(350² +(-250)² +(-450)²)
u=0.562i−0.401j−0.723<span>k
</span>
<span>Force F is directed from point A to B, then both unit vectors must be equal.
Therefore
</span>(x/9i−y/9j−z/9k)=0.562i−0.401j−0.723k
<span>We can now solve for each term
x/9=0.562----- > x=5.058 m
-y/9=-0.401--------- > y=3.609 m
-z/9=-0.723------- > z=6.507 m
The answer is
the coordinates of point a
(5.058,3.609,6.507)
</span>
In the top right corner is -7x since we multiply the x and -7
In the bottom row, we'll have 5x for the first box and -35 for the second box. Each box is the result of multiplying the outer values.
In the top left corner, the x^2 is from multiplying the two copies of x.
