SOLUTION: Hi, I am trying to solve: x(x-3)=21 I tried the distributive property and got x^2-3x=21 I divided each side by 3 x^2-x=7 subtracted x from x^2 and get x=7

Algebra ->  Equations -> SOLUTION: Hi, I am trying to solve: x(x-3)=21 I tried the distributive property and got x^2-3x=21 I divided each side by 3 x^2-x=7 subtracted x from x^2 and get x=7       Log On


   

Question 343428: Hi,
I am trying to solve:
x(x-3)=21
I tried the distributive property and got
x^2-3x=21
I divided each side by 3
x^2-x=7
subtracted x from x^2
and get
x=7
but when I try to work it out, the solution is wrong.. What am I missing? Thank in advance for the help.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
x(x-3)=21
x^2-3x-21 = 0
----
x = [3 +- sqrt(9-4*1*-21)]/2
----
x = [3 +- sqrt(93)]/2
---
Cheers,
Stan H.