Answer:
70x + 490 = 40x +670
Step-by-step explanation:
Let's start with Tom's equation. So we'll start with y=mx+b. b is the amount Tom has started with(aka $490), m is the gain(aka how much money is he getting that month? it's $70) and x is month, plug in the values and you'll get:
y = 70x + 490
Okay do the same thing for Tammy, just change the values accordingly:
y = 40x + 670
Now when are they going to have the same amount of money? This will be the equation to show when they will have the same amount of money. We'll use equal values method:
70x + 490 = 40x +670
subtract 490 and 40x from both sides
30x = 180
divide both sides by 30
x = 6
So, we know now that in 6 months they will have the same amount of money.
