Sheila works for a fishing company. she is paid $20 per day and an additional $2 for each lobster she catches. she wants to know how many lobsters she must catch in order to earn a total of at least $130 after five days of working.

Hey there!
Let's make a linear equation, and we'll plug in our values.
We have:
total = 20 + 2(number of lobsters caught)
We'll have t as total money earned and l as amount of lobsters.
t = 20 + 2l
However, she wants to make 130 dollars in 5 days. We plug in 130 for the total and we multiply the 20 by 5, as that would be her payment in five days excluding the lobsters caught.
130 = 20(5) + 2l
We simplify the right:
130 = 100 + 2l
Subtract 100 from both sides
30 = 2l
Divide both sides by 2
She needs to catch 15 lobsters.
Hope this helps!