Final answer:
To find the number of fence panels needed, Emily should use the equation x = (78 - 6) / 8, which accounts for the gate and divides the remaining length by the length of a panel.
Step-by-step explanation:
The question Emily needs to solve to determine the number of straight fence panels (x) required for her backyard involves simple division. To calculate x, Emily should subtract the length of the gate panel from the total length required and then divide by the length of one fence panel. The correct equation is:
x = (78 - 6) / 8
This equation accounts for the 6-foot-long gate panel and then divides the remaining length by 8 feet, which is the length of each straight fence panel.