Question

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.Explain how you would write a two-variable linear equation for this situation.

Answer 1

ax+by=185
12x+by=185
answer is 12x+y=185

Answer 2

the equation for a two variable equation is ax +by = r

r would be the total number of petri dishes ordered

so you have ax + by = 185

ax would be the number of dished used times x number of days = 12x

so you now have 12x + by = 185

b is unknown so the equation becomes 12x +y = 185