Question

Find the vertex of y = x2 + 14x − 40 by completing the square.

Answer 1

the turning point, vertex can be found by completing the squares
y=x^2 + 14x-40
y=(x+7)^2+7^2-40
y=(x+7)^2+9
the x coordinate is the the opposite of the number in the bracket, that is it's +7 in the bracket so it should be -7
and the y coordinate is the number outside the bracket that us +9

therefore the points are (-7,9)

Answer 2

x = 10 x = 4 Two real solutions:

x =(14+√36)/2=7+3= 10.000

or:

x =(14-√36)/2=7-3= 4.000