Rewriting an equation

Question

Rewrite each equation so that the expression on one side could be graphed and the x-intercepts of the graph would show the solutions to the equation.

1. 3x² = 81

 

Answer 1

3x^2 = 81

x^2 = 27

x^2 - 27 = 0

(x+sqr27)(x-sqr27) = 0

x = + or - sqr27 = + or - 3sqr3 = + or - 3(1.732) = + or - 5.196

Answer 2

 3x² = 81

x^2=27

x=5.1961.......

or negative.