Question

Q3-Which method would best solve the following quadratic?

x^2-81=0
A=Factoring
B=Graphing
C=Square root
D=Completing the square
E=Quadratic formula
Why did you choose the method you chose for question 3?

Answer 1

Square root method is best method to solve the given equation.

Explanation:

The given equation x²-81=0 can be best solved by the square root method. The square root method is best applicable when both the terms are perfect squares. In the equation, x²-81=0, all the terms are perfect squares.

After segregation of terms, a simple square root of the equation would yield the desired result.

x²=81

∴ x= ±9

Since the equation is a polynomial of 2 degrees, the equation would have 2 solutions. Hence the value of x can be either +9 or -9.