f(x)=(x1)(x+2) So its a parabola which crosses the x axis at 1 and 2 obviously.
for part one you shift it 2 to the left so now the x intercepts become 4 and 1.
If you don't see how to draw f(x) expand it it may help.
Maths question

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 30092016 14:33

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 30092016 14:34
(Original post by whydoidothis?)
The textbook is right. 
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 30092016 14:36
(Original post by samantham999)
I have a feeling it is. can you explain? please 
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 30092016 14:37
(Original post by whydoidothis?)
f(x)=(x1)(x+2) So its a parabola which crosses the x axis at 1 and 2 obviously.
for part one you shift it 2 to the left so now the x intercepts become 4 and 1.
If you don't see how to draw f(x) expand it it may help.
I LOVE YOU.
i understand, thank you so much
I knew you had to do something with the equation they gave 
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 30092016 14:40
(Original post by samantham999)
I LOVE YOU.
i understand, thank you so much
I knew you had to do something with the equation they gave 
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 30092016 14:41
(Original post by samantham999)
I thought I was supposed to shift this 2 spaces to the left?
Question 2Bi

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 30092016 14:47
you get 1 & 2
the y intercept is 1x2 (2)
and then plot 
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 30092016 14:49
(Original post by whydoidothis?)
no problem, just get used to reading these types of questions. You knew how to do it, i could tell. If you need any help with AS maths you can PM me. I finished A level maths and got 98% at AS.
I'm doing 6 units this year, I'm finishing chapter 4 in c1 and i'm finding it okayish
I'm really determined to get an A*
Are you studying maths at uni?
and i will pm you for sure when i'm stuck, thanks so much 
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 30092016 14:52
(Original post by samantham999)
Yes thats correct, you just make x1=0 and x+2=0
you get 1 & 2
the y intercept is 1x2 (2)
and then plot 
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 30092016 14:55
(Original post by DylanJ42)
ah someones already helped you, I was just going to say how from this graph is easy to see how shifting everything to the left bt two will give you the graph shown in the answer book
for 2bii) f(x) + 2
I shift 2 unit up right?
and do I start originally from the f(x) = (x1) (x+2) sketch? 
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 30092016 15:03
I took C14 FP12 if you need any help just pm
Posted from TSR Mobile 
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 30092016 15:05
(Original post by samantham999)
I will. I know how to do fx notation with exam solutions but this answer in the textbook doesn't even make sense
did you get an A/A* in maths a level?
i'm doing 6 units this year!! tips?
If you need any help just pm
Posted from TSR Mobile 
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 30092016 15:05

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 30092016 15:08
(Original post by samantham999)
thanks anyway
for 2bii) f(x) + 2
I shift 2 unit up right?
and do I start originally from the f(x) = (x1) (x+2) sketch?
and you do start with (x1)(x+2) yea
basically when you were doing f(x+2) what you are actually doing when you "shift the graph two units to the left" is replacing all the "x"s you see in the function with "x + 2"s.
Think of it like this, if f(x) = (x1)(x+2)
then you could also say, f(q) = (q1)(q+2)
or if you really wanted, f() = (1)(+2) where just like x and q, the just represents a number
so if you have f(x+2) you get ((x+2)1)((x+2)+2) = (x+1)(x+4). This is what you drew in part 2b)i).
Then with f(x) + a, you just write down your function, in this case f(x) is (x1)(x+2) and stick + a on the end
So, f(x) + a = (x1)(x+2) + a
And in your case f(x) + 2 = (x1)(x+2) + 2, which results in the shift upwards of 2 units when you draw the graph 
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 30092016 15:30
(Original post by DylanJ42)
yea thats exactly what you do
and you do start with (x1)(x+2) yea
basically when you were doing f(x+2) what you are actually doing when you "shift the graph two units to the left" is replacing all the "x"s you see in the function with "x + 2"s.
Think of it like this, if f(x) = (x1)(x+2)
then you could also say, f(q) = (q1)(q+2)
or if you really wanted, f() = (1)(+2) where just like x and q, the just represents a number
so if you have f(x+2) you get ((x+2)1)((x+2)+2) = (x+1)(x+4). This is what you drew in part 2b)i).
Then with f(x) + a, you just write down your function, in this case f(x) is (x1)(x+2) and stick + a on the end
So, f(x) + a = (x1)(x+2) + a
And in your case f(x) + 2 = (x1)(x+2) + 2, which results in the shift upwards of 2 units when you draw the graph
I understand now.
but is this the answer?
shouldn't i be back at 0 not going thru it?

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 30092016 15:34
(Original post by samantham999)
I understand now.
but is this the answer?
shouldn't i be back at 0 not going thru it?
therefore f(x) + 2 crosses the x axis at x=0 and x=1 as the answer scheme shows 
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 30092016 15:39
(Original post by DylanJ42)
therefore f(x) + 2 crosses the x axis at x=0 and x=1 as the answer scheme shows 
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 30092016 15:42
(Original post by samantham999)
Ah i feel so dumb, I get the first two but when you expand the bracket how comes you dont do it properly? 
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 30092016 15:45
(Original post by DylanJ42)
dont do it properly. how do you mean? did you learn to expand brackets with FOIL?
x2 + 2x  x 2 +2
x2 + x 2 +2 ?
how do i get to adding x(x+1) on the end?Last edited by 2859410; 30092016 at 15:46. 
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 30092016 15:48
Now I just simplify the x terms ie simplfy , and im left with;
Is that easier to see now?
Now from here you have
do you see how the 2 and + 2 "cancel out" leaving you with;
now factoring out an x gives usLast edited by DylanJ42; 30092016 at 15:50.
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Updated: September 30, 2016
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