Solve the quadratic equation by completing the square.
x^2 +4x- 9=0
first, choose the appropriate form and fill in the blanks with the correct numbers.
then, solve the equation. if there is more than one solution, separate them with commas.

x = -2 ±√13

Step-by-step explanation:

To complete the square, take the middle term bx and divide it in two. Then take the square.

x^2 + 4x - 9 has bx = 4x. Take 4/2 = 2. Square 2^2 = 4.

Now to finish completing the square add 4 to each side.

x^2 + 4x - 9 = 0

x^2 + 4x  + 4 - 9 = 4

(x+2)^2 -9 = 4

Add 9 to both sides and take the square root of each side to solve.

(x+2)^2 = 13

(x+2) = ± √13

x = -2 ±√13

answer: ratio of volume of cone (with 3 times the height and equal diameter) to volume of cylinder is 2 to 1. the value of π is not used.

step-by-step explanation:

radius is diameter/2 = 4.

area of circle is π r^2.

volume of cylinder is height × area of base = hπr^2 = 3(4^2) π = 48π cubic inches.

not knowing the formula for volume of cone, i calculate it using calculus (which is for calculating things).

volume of cone is integral 0 to h area(y) dy. area(y) is π r(y)^2. r(y) runs r to zero as y runs zero to h, r(0) = r, r(h) = 0.

r(y) = r - r/h y

area(y) = π (r - r/h y)^2 = π (r^2 - 2r^2y/h + r^2y^2/h^2) = π r^2(1-2y/h+y^2/h^2)

antiderivative area(y) = π r^2 (y-y^2/h+y^3/(3h^2))

integral 0 to h = π r^2(h-h^2/h+h^3/(3h^2) - (0)) = π r^2(h - h + h/3) = π r^2(h/3) = π/3 r^2 h

volume of this cone is π/3(4^2)18 cubic inches.

= 6 16 π = 96π cubic inches.

cone has twice the volume, 96/48.

cone height is 6 times the cylinder.

ratio of volume formula: π r^2 cancels.

cone over cylinder ratio is 6h/3 to h, 2 to 1.