Answer:
3x + 20 = 80
Step-by-step explanation:
If Sam gets paid $20 a week whether she makes any cakes or not, that is a fixed amount. The amount that she makes will only go up IF she makes cakes. She makes $3 per cake she bakes, and if the number of cakes is our unknown, the expression for that is 3x. Adding that to the fixed amount she makes is 3x + 20. Now we set that equal to 80, which is what she made in a week and solve it for x, which gives us the number of cakes she had to bake to make that $80.
3x + 20 = 80
