I broke maths.

[iNerd]

, yes?

I don't know if I'm doing this right :/

Correct....now simplify further by dividing by a common factor!

[Hutchoo]

Does that mean it's 2 +- (sqrt 6)/2 ?

[Water]

It would mean (4 +- square root 6)/ 2


Your topic name is legendary btw.


PS: Hutchoo, your and my answer are the same, just in different format.

[Hutchoo]

I would of found the answer a lot faster if I didn't think the quadratic formula was:.
Thanks a heap guys, I'll be sure to post up many more year 7 maths questions

[Hutchoo]

A section of a river, as viewed from above, can be modelled by the equation for . Both x and y are measured in km. Bridges cross the river at D(1,16), E(2,15) and F(4.7) find the values of and .

This question is probably easy.. I just graphed it but I don't know what it means by "."

I need help  
Thanks.

[iNerd]

A section of a river, as viewed from above, can be modelled by the equation for . Both x and y are measured in km. Bridges cross the river at D(1,16), E(2,15) and F(4.7) find the values of and .

This question is probably easy.. I just don't know how to approach it, let alone solve it :/

I need help 
Thanks.

I can do that two ways: tech-free or tech-active?

[jasoN-]

well you're given the equation y=ax^2+bx+c
the width of the river can be assumed to be negligible according to the equation, so just take the bridge coordinates to be coordinates on the modeled equation.

sub in the points and use simultaneous equations.

(1,16): 16=a(1)^2+b(1)+c        [1]
(2,15): 15=a(2)^2+b(2)+c        [2]
(4,7):    7=a(4)^2+b(4)+c        [3]

so on..

[iNerd]

^

As above = technology-free.

Technology-active you need to know the certain 'define' feature and other tedious things.

[Hutchoo]

I just edited my post, can someone explain to me what it means by ?

Thanks.

[iNerd]

I just edited my post, can someone explain to me what it means by ?

Thanks.

That is your domain. Domain means your set of x-values.

In more professional notation that is [0,5] so you sketch your graph to your domain.

[jasoN-]

from 0 to 5km (0 is an arbitrary starting point), the river follows that model, from 5+ and 0- the river doesn't follow the model.
its just making the river seem more 'realistic', cos obviously a real river will not follow that model for its entirety

[dooodyo]

In regards to ATAR there is no need to define and sub in instead just use simultaneous equations
and it could be done much more quicker.  

[iNerd]

In regards to ATAR there is no need to define and sub in instead just use simultaneous equations
and it could be done much more quicker.  

We learnt differently :/

Define the function.

solve(f(xvalue)=yvalue and f(xvalue)=yvalue and etc)

[Truck]

In regards to ATAR there is no need to define and sub in instead just use simultaneous equations
and it could be done much more quicker. 

We learnt differently :/

Define the function.

solve(f(xvalue)=yvalue and f(xvalue)=yvalue and etc)

That's assuming you know nothing about the question being asked and JUST how to do it on a calculator.

You'd definitely save heaps of times if you just did solve(3 simultaneous equations, a,b,c etc).

[Hutchoo]

In regards to ATAR there is no need to define and sub in instead just use simultaneous equations
and it could be done much more quicker. 

We learnt differently :/

Define the function.

solve(f(xvalue)=yvalue and f(xvalue)=yvalue and etc)

That's assuming you know nothing about the question being asked and JUST how to do it on a calculator.

You'd definitely save heaps of times if you just did solve(3 simultaneous equations, a,b,c etc).

Yeah, I'm glad you guys showed me how to do it Something similar was on my test today Pretty confident that I got the answer correct.

TY VN <3