Find the axis of symmetry and the vertex of the graph of f(x) = -5x^2 +20x -9.

Axis of Symmetry:

x=2

Vertex:

(2,11)

Step-by-step explanation:

Finding the derivative:

f'(x)=-10x+20

Setting the slope equal to zero:

-10x+20=0      x-2=0    x=2

Finding vertex:

f(2)=-5*(2)^2+20*2-9

=-20+40-9=20-9=11

(2,11)

i think the answer is b.

step-by-step explanation:

not 100% sure though.

answer:

total cost for tiles and paints is $924.  

step-by-step explanation:

we have been given that a community hall is in the shape of a cuboid. the hall is 40m long 15m high and 3m wide.

the paint will be required for 4 walls and ceiling.

let us find area of walls and ceiling.

therefore, the area of walls and ceiling is 1410 square meters.

given: cost for 10 litre of paint is $10 and 10 litre paint covers 25 square meter. therefore,

therefore, the total painting cost is $564.

tiles will be required for floor. let us find the area of floor.

given: 1m squared floor tiles costs $3. so,

therefore, the total tiles cost is $360.

now let us find combined total cost of tiles and paint.

therefore, the combined total cost of tiles and paint is $924.