What is the vertex form of y=x^2 +6x -3 ?

1 Answer
Jan 23, 2016

To convert to vertex form, you must complete the square.

Explanation:

y = x^2 + 6x - 3

y = 1(x^2 + 6x + n) - 3

n = (b/2)^2

n = (6/2)^2

n = 9

y = 1(x^2 + 6x + 9 - 9) - 3

y = 1(x^2 + 6x + 9) -9 - 3

y = 1(x + 3)^2 - 12

So, the vertex form of y = x^2 + 6x - 3 is y = (x + 3)^2 - 12.

Exercises:

  1. Convert each quadratic function from standard form to vertex form:

a) y = x^2 - 12x + 17

b) y = -3x^2 + 18x - 14

c) y = 5x^2 - 11x - 19

  1. Solve for x by completing the square. Leave any non-integer answers in radical form.

a) 2x^2 - 16x + 7 = 0

b) 3x^2 - 11x + 15 = 0

Good luck!