Answer:
The equation to find the profit made by business combined is
.
Business A made $2 million profit and Business B made $8 million profit.
Step-by-step explanation:
Given:
Profit made in previous financial year = $10 million
We need to write an equation to find the profit made by the business.
Solution:
Let the profit (in millions) made by business A be 'x'.
Let the profit (in millions) made by business B be 'y'.
Now given:
business B making 4 times as much profit as business A.
so we can say that;

Now we know that;
Profit made in previous financial year is equal to sum of profit (in millions) made by business A and profit (in millions) made by business B.
framing in equation form we get;

Substituting the value of y in above equation we get;

Hence The equation to find the profit made by business combined is
.
On Solving above equation we get;

profit (in millions) made by business A = 
profit (in millions) made by business B = 
Hence Business A made $2 million profit and Business B made $8 million profit.