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# How to find the y-intercept from this equation

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1. y = 1 - (x - 2)^2

I understand that to get the y intercept, you have to set x = 0?

So y = 1 - (0 - 2)^2

therefore, y = 1 +/- 4 (not really sure which one? should it be positive or negative?)

y = 5 or y = -3

both are wrong tho for some reason? the answer is actually that the y-intercept is -5.
2. .
So . There can be no other answer.
3. (Original post by frostyy)
y = 1 - (x - 2)^2

I understand that to get the y intercept, you have to set x = 0?

So y = 1 - (0 - 2)^2

therefore, y = 1 +/- 4 (not really sure which one? should it be positive or negative?)

y = 5 or y = -3

both are wrong tho for some reason? the answer is actually that the y-intercept is -5.

So
4. (Original post by Zacken)

So
why is the y-intercept equal to -5 then? I swear that y-intercept is when x = 0?
5. (Original post by frostyy)
why is the y-intercept equal to -5 then? I swear that y-intercept is when x = 0?
It's not. Where does it say that it is?
6. (Original post by frostyy)
why is the y-intercept equal to -5 then?
It isn't.

Two people have shown you that the y-intercept is -3.
7. (Original post by frostyy)
y = 1 - (x - 2)^2

I understand that to get the y intercept, you have to set x = 0?

So y = 1 - (0 - 2)^2

therefore, y = 1 +/- 4 (not really sure which one? should it be positive or negative?)

y = 5 or y = -3

both are wrong tho for some reason? the answer is actually that the y-intercept is -5.
Squaring a number always produces a positive so its 1 - (positive number)
8. (Original post by Zacken)
It's not. Where does it say that it is?
Nevermind, I made a mistake whilst completing the square ^^
Sorry for bothering you.
9. (Original post by Xenon17)
Squaring a number always produces a positive so its 1 - (positive number)
Pedantry: .
10. (Original post by frostyy)
Nevermind, I made a mistake whilst completing the square ^^
Sorry for bothering you.
It's not a bother, don't worry.
11. (Original post by Zacken)
Pedantry: .
okay squaring a number never produces a negative.
12. (Original post by Xenon17)
Squaring a number* always produces a positive so its 1 - (positive number)
*Real* number
13. (Original post by Ishan_2000)
OP has said that the answer is actually -5.

However, this can't be right, if the equation of the line is y = 1 - (x - 2)^2
Yeah, that's been established. Also, it's a curve, not a line.

If you sub in y= -5, then x = (square root of 6) + 2, which isn't 0, so -5 cannot be the y-intercept.
Or the simple observation that suffices.

(How do you use LaText on this? )
The guide is here.
14. (Original post by Xenon17)
okay squaring a number never produces a negative.
Yep! In mathematical terms, we say: squares are non-negative.
15. (Original post by B_9710)
*Real* number
Okay calm down no need to get your knickers in a twist.
16. (Original post by Zacken)
Yep! In mathematical terms, we say: squares are non-negative.
I prefer thug life terms sorry
17. (Original post by Xenon17)
I prefer thug life terms sorry
It's the maths forum not the thug life forum sorry
18. Wouldn't really call something that basic 'Mathematical terms'
19. (Original post by Zacken)
It's the maths forum not the thug life forum sorry
the thug life is universal
20. (Original post by Foxab77)
Wouldn't really call something that basic 'Mathematical terms'
Uh... I don't see why being basic means that it's not a mathematical term... is 'addition' so basic that you'd say it's not a mathematical term?

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