Phineas is the lead research scientist in a lab and responsible for ordering supplies and equipment. the lab is out of petri dishes, so phineas orders 185 of them. the lab uses 12 petri dishes each day.

The answer is 12x + y = 185

The common formula for a two variable linear equation is: ax + by = r

The lab starts with 185 dishes which is y-intercept:
ax + by = 185

The number of dishes used per day is 12 which is slope:
12x +by = 185

Therefore, the two variable linear equation for this example is 12x + y = 185.