Answer:
- j = 7x +40; s = 5x +50
- x = 5
Explanation:
Jacob is saving $7 per week, so after x weeks, he has saved 7x in addition to the $40 he started with:
j = 7x +40
Similarly, Savannah is saving $5 per week in addition to the $50 she started with, so her savings will be ...
s = 5x +50
Jacob and Savannah will have the same amount of money when ...
j = s
7x +40 = 5x +50 . . . . substitute for j and s
2x +40 = 50 . . . . . . . . subtract 5x from both sides
2x = 10 . . . . . . . . . . . . subtract 40 from both sides
x = 5 . . . . . . . . . . . . . . divide both sides by 2
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Comment on the equations
I used j and s for the amounts that Jacob and Savannah accumulated, because I like to use variable names that remind me what they stand for. You may be expected to write these as y = equations, where y stands for the amount each person has saved.