SOLUTION: My son has just entered grade 8 in high school and has asked me to solve this equation, 9x²-36=9(x²-4)-9(x+2)(x-2) he says x=? I would be greatfull for any help Thanks John

Algebra ->  Equations -> SOLUTION: My son has just entered grade 8 in high school and has asked me to solve this equation, 9x²-36=9(x²-4)-9(x+2)(x-2) he says x=? I would be greatfull for any help Thanks John      Log On


   

Question 155296: My son has just entered grade 8 in high school and has asked me to solve this equation,
9x²-36=9(x²-4)-9(x+2)(x-2) he says x=?
I would be greatfull for any help
Thanks
John
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
9x²-36=9(x²-4)-9(x+2)(x-2)
9x²-36=9x²-36-9(x²-4)
9x²-36=9x²-36-9x²+36
-36=-36-9x²+36
0=0-9x²+36
9x²=36
x²=4
x = sqrt(4)
x = {-2,2}
.
x is plus or minus 2