please help and explain. I do not understand

Factory Overhead Controllable Variance Bellingham Company produced 6,800 units of product that required 7.5 standard hours per unit. The standard variable overhead cost per unit is $6.30 per hour. The actual variable factory overhead was $314,870. Determine the variable factory overhead controllable variance. Enter a favorable variance as a negative number using a minus sign and an unfavorable variance as a positive number