Answer:
X=9 or x=-9
Step-by-step explanation:
X^2=81
Can be written as
x^2-81=0
Factorize by the property:
a^2-b^2=(a-b)(a+b)
So the expression becomes:
(x-9)(x+9)=0
Therefore, either x-9=0or x+9=0
Then the solutions are x=9 or x=-9
Use the formula i=prt, where i is the interest earned, p is the principal, r is the rate (as a decimal fraction) and t is the elapsed time, in years.
Here i = $72 = $1200 r (9/12) (9 months is 9/12, or 3/4, of 1 year)
Reducing,
$72 = $900r
Solving for r, r=0.08, or 8 percent per year.
Answer:
25 kids are in the class
Step-by-step explanation:
