maths

[Tahmina]

is anyone gd at quadratics
i hav my summer exams next next
i need help on this question

Make X the subject of the formula y= 3x+4 divide by x-3


ta:)

[GreyKode]

is anyone gd at quadratics
i hav my summer exams next next
i need help on this question

Make X the subject of the formula y= 3x+4 divide by x-3


ta:)

I can try to help out if you could only clarify the question.

[alcurad]

you mean as (x=) instead of (y=) then divide by (x-3) ?

I don't understand the last part, but here goes:
consider / as division, then:
y = 3x + 4

y - 4 = 3x + 4 - 4

(y - 4) / 3 = 3x / 3

(y - 4) / 3 = x

I hope that helped :)

[Tahmina]

yes it is
can you help

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[~Raynn~]

^ Okey dokey, in which case...

y = (3x + 4)/(x - 3)

(x - 3)y = 3x + 4 .....[multiply both sides by x - 3]

xy - 3y = 3x + 4 .....[expand the brackets]

xy - 3x = 3y + 4 .....[bring all the x terms on one side]

x (y - 3) = 3y + 4 .....[take out a factor of x]

x = (3y + 4)/(y - 3) .....[divide both sides by y - 3]

Hope that helps!

[alcurad]

ah i see, then is it (3x-4)/(3-x) or just 3x-[4/(3-x)]?

[~Raynn~]

^ Nope, nope, that's exactly right! And if you take out a factor of -1 in both the top and bottom, and cancel them out, you get the same form...but it kinda looks nicer with less -ve signs, lol :D.

[~Raynn~]

:giggling: Terrrible...not that it makes any difference whatsoever, of course, lol...

[Tahmina]

thanks that helped
:happy: