Question 308025
Not really an algebra problem but here's how it's done.
The sum of the forces equals mass multiplied by acceleration. 
I'm assuming the force applied by the tractor ({{{T}}}) is perpendicular to the weight of the sled ({{{W=mg}}}). The forces acting are the weight in the y direction (up-down) and an equal and opposite force from the floor so that y acceleration is zero. 
Friction acts in the direction to oppose movement (opposite the tractor pull force) and is equal to the product of the weight ({{{W}}}) and friction coefficent ({{{mu}}}).
{{{F=ma=T-mu*W}}}
{{{a=(T-mu*mg)/m=(1300-(0.8)11000(9.8))/11000}}}
Since the friction force is greater than the force applied by the tractor, the sled does not move. 
The tractor has to apply a force at least greater than {{{mu*mg=86240}}} N to accelerate the sled. Any force less than that will not move the sled. 
{{{a=0}}}