1) -7.14 N
2) +2.70 N
3) 7.63 N
Explanation:
1)
In order to find the x-component of the resultant force, we have to resolve each force along the x-axis.
The first force is 8.00 N and is directed at an angle of 61.0° above the negative x axis in the second quadrant: this means that the angle with respect to the positive x axis is

so its x-component is

F₂ has a magnitude of 5.40 N and is directed at an angle of 52.8° below the negative x axis in the third quadrant: so, its angle with respect to the positive x-axis is

Therefore its x-component is

So, the x-component of the resultant force is

2)
In order to find the y-component of the resultant force, we have to resolve each force along the y-axis.
The first force is 8.00 N and is directed at an angle of 61.0° above the negative x axis in the second quadrant: as we said previously, the angle with respect to the positive x axis is

so its y-component is

F₂ has a magnitude of 5.40 N and is directed at an angle of 52.8° below the negative x axis in the third quadrant: as we said previously, its angle with respect to the positive x-axis is

Therefore its y-component is

So, the y-component of the resultant force is

3)
The two components of the resultant force representent the sides of a right triangle, of which the resultant force corresponds tot he hypothenuse.
Therefore, we can find the magnitude of the resultant force by using Pythagorean's theorem:

Where in this problem, we have:
is the x-component
is the y-component
And substituting, we find:
