Answer:
C: isolate the x squared by using inverse operations
Step-by-step explanation:
This method of solving quadratic equation is used when there is only x² term and no x term. Thus;
For example, we have a quadratic equation;
x² - 1 = 80
To solve this by square root method, the first step we have to take is to isolate the x² term by inverse operation which is by addition of 1 to both sides to get rid of the -1 on the left side so that x² can be isolated.
Your sister would be 66.
When you are 10, your sister would be 6 (10-4=6)
60 years later, you would be 70, and your sister would still be 4 years younger.
Since this is a problem of simple interest, then the interest earned will be based always on the principal amount which is 5000. So assuming that, lets also assume that the duration to get interest will be in years since that is the most commonly used duration anyway. So first, let's multiply 5000 with 0.075 to get the interest for the first year. So we will have 375. This means that we will be getting 375 interest every year. We can do trial an error method to get the number of years that will yield us to 6500. Through that, I was able to get 4 years. So 4 times 375 equals 1500 plus the original balance of 5000. It will take 4 years before your balance reaches 6500
