Look at this video: https://www.khanacademy.org/math/cc-fifth-grade-math/cc-5th-fractions-topic/cc-5th-multiplying-fraction-whole-number-product
The slope is 10. For every 1 increase in x, y increases by 10.
take x =initial deposit amount. then make equation:
x+75.5+55.25-25.15-18.65 = 210.85
simplify:
x+86.95 = 210.85
x=210.85 - 86.95
x=123.90
so Initial deposit amount is $123.90
check: 210.85+18.65+25.15-55.25-75.5 = 123.9
123.9 = 123.9
-10.6, and 9/10, are the constants
