Common Mistakes When Completing The S...

Scribe: Kelsey Knight.
Common Mistakes When Completing The Square:
Forgetting to add (B/2)² on both sides.
Forgetting ± when taking the square root of each side.
Not Factoring Out the leading coefficients number.
Not finishing solving the equation for X after finding C.
Forgetting to move the constant to the other side of the equation before completing the square.
Fighting the temptations to deal with DECIMALS, learn to use FRACTIONS.

Questions:

-What to do after you multiply B by ½?
X² + 2X= 13
(2/2)² + X²  + 2X = 13 + (2/2)²     <- Add (B/2)²  to each side, in this equation (B/2)²  is (2/2)²
(2/2)² = 1
X² + 2X + 1 = 13 + 1
(X+1)² = 14
㊦(X+1)²= ㊦




14 <- Take the square root of each side.
(X+1) = ±㊦




14 <- Add A ± Sign.
X= 1+ ㊦14 OR
X= 1- ㊦14
There Are two answers because of the ± Sign.

-What to do if the x² coefficient is multiplied
by a number that is greater than 1?