SOLUTION: I dont even understand this problem at all. 81x^2-144=0. Whoever solves this, then i wish you the best because it's difficult.

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: I dont even understand this problem at all. 81x^2-144=0. Whoever solves this, then i wish you the best because it's difficult.      Log On


   

Question 148769: I dont even understand this problem at all. 81x^2-144=0. Whoever solves this, then i wish you the best because it's difficult.
Found 2 solutions by nerdybill, jim_thompson5910:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
Notice that you can "factor" it:
81x^2-144=0
(9x+12)(9-12)=0
.
therefore:
x = {-12,12}

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

81x%5E2-144=0 Start with the given equation.


81x%5E2=0%2B144 Add 144 to both sides.


81x%5E2=144 Combine like terms on the right side.


x%5E2=%28144%29%2F%2881%29 Divide both sides by 81 to isolate x%5E2.


x%5E2=16%2F9 Reduce.


x=0%2B-sqrt%2816%2F9%29 Take the square root of both sides.


x=sqrt%2816%2F9%29 or x=-sqrt%2816%2F9%29 Break up the expression


x=sqrt%2816%29%2Fsqrt%289%29 or x=-sqrt%2816%29%2Fsqrt%289%29 Break up the square root.


x=4%2F3 or x=-4%2F3 Take square root of 16 to get 4. Take square root of 9 to get 3.


So the answers are x=4%2F3 or x=-4%2F3