From 6x2−7xy+8y2 subtract the sum of x2−3xy−y2 and 2x2+5xy−4y2 *every 2 is supposed to resemle -to the power of two- it just woudn't let me type it like that.

The sum of x^2−3xy−y^2 and 2x^2+5xy−4y^2:

x^2−3xy−y^2 + 2x^2+5xy−4y^2

= 3x^2 + 2xy - 5y^2

From 6x^2−7xy+8y^2 subtract the sum of x^2−3xy−y^2 and 2x^2+5xy−4y^2:

6x^2−7xy+8y^2 - (3x^2 + 2xy - 5y^2)

= 6x^2−7xy+8y^2 - 3x^2 - 2xy + 5y^2

= 3x^2−9xy + 13y^2

Answer

3x^2−9xy + 13y^2

  the correct choice is marked

step-by-step explanation:

the first two graphs show multiple turning points. the last graphs matches the description in every detail.

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.