McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
4. Transformations of Quadratic Graphs
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Exercise 1 Page 203

Start by identifying a, b, and c. Then use the expression - b2a to find the x-coordinate of the vertex.

y=(x+3)^2-7

Practice makes perfect
We have a quadratic function written in standard form, and we want to rewrite it in vertex form. Standard Form:& y= ax^2+ bx+c Given Equation:& y= 1x^2+ 6x+2 In the given equation, a= 1, b= 6, and c=2. Let's now recall the vertex form of a quadratic function. Vertex Form: y=a(x-h)^2+k In this equation, a is the leading coefficient of the quadratic function, and the point (h,k) is the vertex of the parabola. By substituting our given values for a and b into the expression - b2a, we can find h.
- b/2a
- 6/2( 1)
â–¼
Simplify
- 6/2
- 3
So far, we know that the vertex lies at (-3,k). To find the y-coordinate k, we will substitute -3 for x in the given function.
y=x^2+6x+2
y=( -3)^2+6( -3)+2
â–¼
Simplify right-hand side
y=9+6(-3)+2
y=9-18+2
y=-7
Therefore, the (h,k) coordinate pair of the vertex is (-3,-7). Moreover, since we already know that a= -2, we can rewrite the given function in vertex form. y= 1 (x-(-3))^2+(-7) ⇔ y = (x+3)^2-7