simultaneous equations

**mark** · October 19th 2009, 02:28 AM

hi i've got the question: solve the simultaneous equations $2x + y = 9$ and $(x - 2)^2 + y^2 = 5$

can someone show me how this would be done please? thanks

**mathaddict** · October 19th 2009, 02:40 AM

Originally Posted by mark

hi i've got the question: solve the simultaneous equations $2x + y = 9$ and $(x - 2)^2 + y^2 = 5$

can someone show me how this would be done please? thanks

HI

$2x+y=9$ --1

From 1 , $y=9-2x$

$(x-2)^2+y^2=5$

Substitute $(x-2)^2+(9-2x)^2=5$

$x^2-4x+4+81-36x+4x^2-5=0$

$x^2-8x+16=0$

$x=4$

$y=9-2(4)$

$<br /> =1<br />$

**stapel** · October 19th 2009, 04:50 AM

Originally Posted by mark

can someone show me how this would be done please?

Ouch! They were supposed to have covered this in class and in your text before assigning questions on it!

To learn "how this would be done", try an online lesson or two. Be sure to study the worked examples.

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