What is the vertex form of y=13x^2 +3x- 36 y=13x2+3x36?

1 Answer
Feb 1, 2016

vertex form: y=(x+3/26)^2-1881/52y=(x+326)2188152

Explanation:

1. Factor 13 from the first two terms.

y=13x^2+3x-36y=13x2+3x36

y=13(x^2+3/13x)-36y=13(x2+313x)36

2. Turn the bracketed terms into a perfect square trinomial.
When a perfect square trinomial is in the form ax^2+bx+cax2+bx+c, the cc value is (b/2)^2(b2)2. Thus you divide 3/13313 by 22 and square the value.

y=13(x^2+3/13x+(3/13x-:2)^2)-36y=13(x2+313x+(313x÷2)2)36

y=13(x^2+3/13x+9/676)-36y=13(x2+313x+9676)36

3. Subtract 9/676 from the perfect square trinomial.
You cannot just add 9/6769676 to the equation, so you must subtract it from the 9/6769676 you just added.

y=13(x^2+3/13x+9/676y=13(x2+313x+9676 color(red)(-9/676))-369676)36

4. Multiply -9/676 by 13.
The next step is to bring -9/6769676 out of the brackets. To do this, multiply -9/6769676 by the aa value, 1313.

y=color(blue)13(x^2+3/13x+9/676)-36[color(red)((-9/676))*color(blue)((13))]y=13(x2+313x+9676)36[(9676)(13)]

5. Simplify.

y=(x^2+3/13x+9/676)-36-9/52y=(x2+313x+9676)36952

y=(x^2+3/13x+9/676)-1881/52y=(x2+313x+9676)188152

6. Factor the perfect square trinomial.
The last step is to factor the perfect square trinomial. This will allow you to determine the coordinates of the vertex.

color(green)(y=(x+3/26)^2-1881/52)y=(x+326)2188152

:., the vertex form is y=(x+3/26)^2-1881/52.