PLEASE I NEED HELP Pierre was plotting the quadratic function f(x)=-x^2+8x for an exit ticket. his work is shown to the right.

Part A: Complete the table below and graph function on the same coordinate system above.
X f(x) X f(x)
0 5
1 6
2 7
3 8
4

Part B: His teacher marked it incorrect. Explain why Pierre's work was counted incorrect.

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb

so a parallelogram is just like a square base times height. multiply 40 and 39 to get 1560 inches.

a triangle is base times height divided by two. so multiply 7.9 and 5 and then divide it by 2 to get 19.75inches.

the kite can be split into two separate triangles and added together to get the total area. 30 x 4 /2 which equals 60. make sure to double it for the two triangles making 120.