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Reply 40
namedeprived
When you have a fraction, remember that if you can multiply both the numerator and denominator by a certain the fraction remains the same. Multiply the numerator and the denominator of the first fraction by some expression involving x and multiply the second fraction by a differentexpression involving x, so that both fractions have the same denominator.

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That's brilliant thank you!
In the following question, how would I find out the numbers which go in place of the question marks?

x2+5x+3=0x^2+5x+3=0

I got so far into the next step and got lost...

(x+?)(x+?)=0(x+?)(x+?)=0

Could you tell me how to find values for the 2 question marks please. I thought you had to find 2 numbers which you can multiply to give you 3, but also add up to 5?

Thanks for your help
Quintro
That's brilliant thank you!
In the following question, how would I find out the numbers which go in place of the question marks?

x2+5x+3=0x^2+5x+3=0

I got so far into the next step and got lost...

(x+?)(x+?)=0(x+?)(x+?)=0

Could you tell me how to find values for the 2 question marks please. I thought you had to find 2 numbers which you can multiply to give you 3, but also add up to 5?

Thanks for your help


It won't factorise. Use the quadratic formula, or completing the square (don't know if the latter is taught at Int 2)
Reply 42
namedeprived
It won't factorise. Use the quadratic formula, or completing the square (don't know if the latter is taught at Int 2)

I knew something wasn't right when I was trying to factorise. I forgot all about the quadratic formula as we haven't done it in ages but I looked over it and I've got it now! Hopefully this comes up tomorrow in my prelim..

Thanks again
Quintro
Nice that's really useful.


Just to add to what namedeprived said, or to at least make something more explicit, you have to remember not to divide by zero when you're dividing by a variable, which can be quite subtle.

Consider these non-proofs that hinge on hiding the division by zero in this way.
Reply 44
Quintro
I knew something wasn't right when I was trying to factorise. I forgot all about the quadratic formula as we haven't done it in ages but I looked over it and I've got it now! Hopefully this comes up tomorrow in my prelim..

Thanks again


Good luck, I'm sure you will pass with ease...
TheUnbeliever
Just to add to what namedeprived said, or to at least make something more explicit, you have to remember not to divide by zero when you're dividing by a variable, which can be quite subtle.

Consider these non-proofs that hinge on hiding the division by zero in this way.


Just realised that I said
namedeprived
so long as you don't divide by 0!
which is clearly equal to 1.:biggrin:
Reply 46
Thanks for the help and support everyone. :smile:

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