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43 votes
43 votes
Could i have some super super quick help? :(( (part iv is not necessary)

might be getting the hang of it but i would still like some help

Could i have some super super quick help? :(( (part iv is not necessary) might be-example-1
User Lilliana
by
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2 Answers

14 votes
14 votes
  • y=-x²+16x-64

#1

  • y=-x²+8x+8x-64
  • y=-x(x+8)+8(x+8)
  • y=(x+8)(-x+8)
  • y=-(x-8)(x-8)

#2

Zeros are the x intercepts

Here they are

  • 8,8

#3

  • y=-x²+16x-64
  • y=-[x²-16x+64]
  • y=-(x-8)²+0

Vertex form of parabola:-y=a(x-h)²+k

  • Vertex=(h,k)=(8,0)

#4

Attached

Could i have some super super quick help? :(( (part iv is not necessary) might be-example-1
User SatishBoddu
by
2.2k points
17 votes
17 votes

i)

Factor using completing square method


\dashrightarrow \sf y = -x^2+16x-64


\dashrightarrow \sf y = -(x^2-16x+64)


\dashrightarrow \sf y = -(x^2-8x-8x+64)


\dashrightarrow \sf y = -(x(x-8)-8(x-8))


\dashrightarrow \sf y = -((x-8)(x-8))

ii)

Find zeros of a function, f(x) = 0


\dashrightarrow \sf -((x-8)(x-8))=0


\dashrightarrow \sf (x-8)=0, \ (x-8)=0


\dashrightarrow \sf x = 8

iii)

In order to find vertex use the formulae : x = -b/2a


\dashrightarrow \sf x = (-(16))/(2(-1))


\dashrightarrow \sf x = 8

Then find y:


\dashrightarrow \sf y = -(8)^2+16(8)-64


\dashrightarrow \sf y = 0

coordinates: (8, 0)

iv) Sketched Below:

Could i have some super super quick help? :(( (part iv is not necessary) might be-example-1
User Rocky Singh
by
2.6k points