SOLUTION: I am having trouble with a question on Quadratic Equations. It says: SOLVE EACH EQUATION BY COMPLETING THE SQUARE {{{ x^2+10x-11=0 }}} {{{ p^2-8p+12=0 }}} {{{ r^2-2r-15

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: I am having trouble with a question on Quadratic Equations. It says: SOLVE EACH EQUATION BY COMPLETING THE SQUARE {{{ x^2+10x-11=0 }}} {{{ p^2-8p+12=0 }}} {{{ r^2-2r-15      Log On


   

Question 846042: I am having trouble with a question on Quadratic Equations. It says:
SOLVE EACH EQUATION BY COMPLETING THE SQUARE
+x%5E2%2B10x-11=0+
+p%5E2-8p%2B12=0+
+r%5E2-2r-15=0+
My answers are;
x= 1, -11
p= 6, 2
r= 3, -5
The grading system says they are wrong, but it does make make mistakes sometimes.
Found 2 solutions by psbhowmick, ewatrrr:
Answer by psbhowmick(878) About Me  (Show Source):
You can put this solution on YOUR website!
r%5E2-2r-15=0
%28r%5E2-2%2Ar%2A1%2B1%5E2%29-1%5E2-15=0
%28r-1%29%5E2-1-15=0
%28r-1%29%5E2=16
x+=+1+%2B-+sqrt%2816%29
x+=+1+%2B-+4
x+=+-3,5
Your other answers look correct!

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

factoring  (smaller value listed first for solutions)

+x%5E2%2B10x-11=+%28x%2B11%29%28x-1%29+=+0+  x = -11,1



+p%5E2-8p%2B12=+%28p-6%29%28p-2%29+=+0+   p = 2, 6



+r%5E2-2r-15=+%28r-5%29%28r%2B3%29+       r = -3, 5      ****