Answer:
9
Step-by-step explanation:
Compare your x2 + y2=81 to the following:
x^2 + y^2 = 81
The " ^ " symbol indicates exponentiation.
Now compare x^2 + y^2 = 81 to
x^2 + y^2 = r^2.
This is the standard equation of a circle of radius r centered at the origin, (0,0). You can see for yourself that 81 must equal r^2.
Taking the square root of 81, we get plus or minus 9.
But the radius must be positive, so we reject the -9 and take +9.
The radius is 9.
Answer:
It takes 75 years for the investment to quadruple in value
Step-by-step explanation:
Simple Interest
This is a simple interest problem.
The simple interest formula is given by:
In which E is the amount of interest earned, P is the principal(the initial amount of money), I is the interest rate(yearly, as a decimal) and t is the time.
After t years, the total amount of money is:
In this question:
4% simple interest per year, so I = 0.04.
Quadruple:
t when T = 4P.
The interest earned is:
Now we find the time.
It takes 75 years for the investment to quadruple in value
I think it is moving backward because when a car is parking and you are leaving, then you would be moving backward.
Hope this helped☺☺
Are you add or subtracting
SUBTRACTION
3 1/4- 1 1/4 = 1 3/4
Addition
3 1/4-1 1/4= 4 3/4