SOLUTION: 3. -9(x-3)^2=-7 I got as far as x-3=rs 7/3 no radical sign. Now I then do x=3/5 rs over the three and times it by 9/5. Do I multiply the 7 times the nine or or just leave i

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: 3. -9(x-3)^2=-7 I got as far as x-3=rs 7/3 no radical sign. Now I then do x=3/5 rs over the three and times it by 9/5. Do I multiply the 7 times the nine or or just leave i      Log On


   

Question 62388: 3. -9(x-3)^2=-7
I got as far as x-3=rs 7/3 no radical sign.
Now I then do x=3/5 rs over the three and times it by 9/5. Do I multiply the 7 times the nine or or just leave it as 9 plus or negative over 7/3.
Found 3 solutions by stanbon, funmath, checkley71:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
-9(x-3)^2=-7
(x-3)^2=7/9
Take the sqrt of both sides to get:
x-3=sqrt7/3
x=(sqrt7)/3 + 3
Cheers,
Stan H.

Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
You were almost done, you forgot that when you take the square root of both sides of an equation it's +/- the other side. All you would need, then is to add 3 to both sides.
3. -9%28x-3%29%5E2=-7
-9%28x-3%29%5E2%2F-9=-7%2F-9
%28x-3%29%5E2=7%2F9
sqrt%28%28x-3%29%5E2%29=%2B-sqrt%287%2F9%29
x-3=%2B-sqrt%287%29%2F3
x-3%2B3=3%2B-sqrt%287%29%2F3
x=3-sqrt%287%29%2F3 and x=3%2Bsqrt%287%29%2F3 <---this is fine
x=%289-sqrt%287%29%29%2F3 and x=%289%2Bsqrt%287%29%29%2F3 is also fine.
Happy Calculating!!!

Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
-9(x-3)^2=-7
-9(x^2-6x+9)=-7
-9x^2+54x-81=-7
-9x^2+54x-81+7=0
-9x^2+54x-74=0
9x^2-54x+74=0 using the quadratic equation x=(-b+-sqrt[b^2-4ac)]/2a we get
x=(54+-sqrt[-54*-54-4*9*74)]/2*9
x=(54+-sqrt[2916-2664])/18
x=(54+-sqrt-252)/18
x=(54+-15.87)/18
x=54+15.87)/18
x=69.87/18
x=3.88 solution
x=(54-15.87)/18
x=38.13/18
x=2.12 solution
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ALL THESE ANSWERS ARE CORRECT. THEY ARE JUST IN DIFFERENT FORMS. IF YOU'LL SOLVE THE OTHER SOLUTIONS WITH THE RADICAL SIGNS YOU'LL SEE THEY GET THE SAME NUMBERS AS I GOT.