Both equations can be shown with the linear equation— Y = MX + B
Since M is your slope (how much it goes up each month, we now have: Y= 60X + B
Since B is your y-intercept (how much we have starting off), we now have: Y= 60X + 460. I’m not sure if it wants you to write is as $=60x+460 or Y=$60x+$460, so that’s up to you.
Now that we understand how to substitute the variables, we can now do the same for Jina: Y= 50x+530.
In order to find out when they will have the same amount of money, we put their equations into an equation (you’ll see what I mean):
60x+460=50x+530
Now we can start solving.
First, we need to isolate the X on one side. So, we subtract 50x from both sides.
10x+460=530
Now we subtract 460 from both sides.
10x= 70
Finally, we get rid of the coefficient (10) by dividing both sides by it.
X=7
Now that we are left with this, we know that after 7 months, both Jina and Alan have the same amount of money. The equation we used to solve for X is what your answer is for number 3.