Question

write the following quadratics in the form
y=(x-h)^2 +k using completing the squares and hence sketch each function and stating the vertex
a) y= x^2 -6x+5
b) y= x^2 +8x -2

Answer 1

a)
y=x^2-6x+5
y=x^2-6x+9-4
y=(x-3)^2+(-4)
vertex (3,-4)
b)
y=x^2+8x+5
y=x^2+8x+16-21
y=(x+4)^2-21
y=(x-(-4))^2-21
vertex (-4,-21)

Answer 2

b. not is correct

Answer 3

why -21 ?

Answer 4

just -11

Answer 5

right ???

Answer 6

but in point b. there is +2 and not +5 like last term

Answer 7

sorry -11

Answer 8

oh not +5 there is -2

Answer 9

y=x^2+8x+5
y=x^2+8x+16-11
y=(x+4)^2-11
y=(x-(-4))^2-11
vertex (-4,-11)

Answer 10

hmmm i think its supposed to be 18?

Answer 11

woopppss the question b) was supposed to be x^2+8x-2

Answer 12

you need checking how can you get 8 can us 6+2 or 4+4 or 5+3 or 7+1 or ????

Answer 13

instead of +5 haha

Answer 14

sorry kirsten i solved for +5
y=(x-(-4))^2-18
vertex (-4,-18)

Answer 15

yes and after you check how can you getting the needed number what will result from product of used numbers for 8 and after you will get how many you need subtracting from that

Answer 16

ok ?

Answer 17

yapppp :) awesome thank you guys