The Student Room Group

Help me with coordinate geometry please ?

State the equation of the line of symmetry of the curve :
y=x^2+5x+7.
so if you complete the square you get

y = ( x + a )2 + b

and the symmetry line is x = - a
Line of symmetry is -b/2a using the quadratic equation for a b and c
Original post by AlanAnonymouss
Line of symmetry is -b/2a using the quadratic equation for a b and c


-b/2a is not an equation Alan.
Original post by the bear
so if you complete the square you get

y = ( x + a )2 + b

and the symmetry line is x = - a


Naughty bear giving the answer!
Original post by the bear
-b/2a is not an equation Alan.


1F6F5683-9012-4645-8BBC-9D827534CD56.jpg.jpeg
Original post by AlanAnonymouss
1F6F5683-9012-4645-8BBC-9D827534CD56.jpg.jpeg


This was really helpful thank you
Original post by Muttley79
Naughty bear giving the answer!


ermm i so did not :mad:

Muttley = :spank:
Original post by the bear
so if you complete the square you get

y = ( x + a )2 + b

and the symmetry line is x = - a

Thank you bear.
Original post by kurro
Thank you bear.


your welcome

:borat:

:badger:
Original post by the bear
-b/2a is not an equation Alan.


Indeed. It's an expression. C'mon, Alan. What you playing at...
Original post by AlanAnonymouss
Line of symmetry is -b/2a using the quadratic equation for a b and c


OMFG Alan......
Original post by the bear
ermm i so did not :mad:

Muttley = :spank:


I think you need the spanking bear - the OP has no reason to understand why completing the square 'works' or why it is a good approach. You've just told them what to do!
Original post by Muttley79
I think you need the spanking bear - the OP has no reason to understand why completing the square 'works' or why it is a good approach. You've just told them what to do!


they can research it ... it is the standard method.
Original post by the bear
they can research it ... it is the standard method.


It's 'a' standard method - you are usually good at just giving a hint ...

Has bear got a sore head this morning?
Original post by Muttley79
It's 'a' standard method - you are usually good at just giving a hint ...

Has bear got a sore head this morning?


:eviltongue:

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