Answer:
0.0078 N
Explanation:
The electrostatic force between two charges is given by Coulomb's law:
where:
is the Coulomb's constant
are the two charges
r is the separation between the two charges
The force is attractive if the two charges have opposite sign, and repulsive if the two charges have same sign.
In this problem, we have:
located at 
located at 
located at 
The force between charge 1 and charge 2 is:

And since the two charges have opposite sign, the force is attractive, so the force on charge 1 is towards the right.
The force between charge 1 and charge 3 is:

And since the two charges have same sign, the force is repulsive, so the force on charge 1 is towards the left.
Therefore, the net force on charge 1 is:

towards the right.
It would be helpful if you draw the figure of the problem. You will see that a right triangle would be constructed by the problem where 19.0 is the angle between the hypotenuse and the base of the triangle. It is said that the force acting is said to be 9.0 N at the said angle to the horizontal. Using trigonometric relations,
cos 19 = adjacent / hypotenuse = horizontal component / 9
horizontal component = 8.51 N