What is the vertex form of y=−9x2+12x−18? Algebra Quadratic Equations and Functions Vertex Form of a Quadratic Equation 1 Answer Noah G · Suryin =) Dec 26, 2015 Below is the proof (a completion of square) Explanation: y=−9x2+12x−18 y=−9(x2−129x)−18 y=−9(x2−129x+_ - _ ) - 18# _=(−1292)2 _=49 y=−9(x2−129x+49)−49(−9)−18 y=−9(x−23)2−14 So, y=−9x2+12x−18 is equal to y=−9(x−23)2−14 Hopefully that explanation helped! Answer link Related questions What is the Vertex Form of a Quadratic Equation? How do you find the vertex form of a quadratic equation? How do you graph quadratic equations written in vertex form? How do you write y+1=−2x2−x in the vertex form? How do you write the quadratic equation given a=−2 and the vertex (−5,0)? What is the quadratic equation containing (5, 2) and vertex (1, –2)? How do you find the vertex, x-intercept, y-intercept, and graph the equation y=−4x2+20x−24? How do you write y=9x2+3x−10 in vertex form? What is the vertex of y=−12(x−4)2−7? What is the vertex form of y=x2−6x+6? See all questions in Vertex Form of a Quadratic Equation Impact of this question 1737 views around the world You can reuse this answer Creative Commons License