16.5k views
4 votes
X squared -6x=7 for completing the square

User HanXu
by
7.9k points

1 Answer

5 votes
take 1/2 of linear coefient (-6), so 1/2 of -6 is -3
square it ( (-3)^2=9)
add that to both sides

x^2-6x+9=7+9

x^2-6x+9=16
factor perfect square trinomial

(x-3)^2=16
sqrt both sides, remember to take positive and negative roots
x-3=+/-4
add 3
x=3+/-4
x=-1 or 7
User Mandar Vaze
by
8.7k points