Math Is Fun Forum

pkaur

Member

Registered: 2013-12-26

Posts: 1

URGENT!!!!!!!non linear simultaneous equations

URGENT
i know the answers to all of the following but do not know how to get the answer, each of them include simultaneous equations and the quadratic equation:

a)
x-y+1=0 and 3x^2-4y=0
the answer is 2,3 or -2/3, 1/3

b)
x^2+xy=8 and x-y=6
the answer is 4,-2 or -1,-7

c)
2x-y+3=0 and y^2-5x^2=20
the answer is 1,5 or 11,25

d)
x=2y and x^2-y^2+xy=20
the answer is 4,2 or -4,-2

e)
x+2y=-3 and x^2-2x+3y^2=11
the answer is 1,-2 or -2 3/2, -2/7

NEED URGENT HELP!!!!
no explanation needed.... will figure it out myself, just layout the working out please

thanks before hand!

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: URGENT!!!!!!!non linear simultaneous equations

Hi;

a)
x-y+1=0 and 3x^2-4y=0
the answer is 2,3 or -2/3, 1/3

Take the first equation and solve for y.

Now substitute that y into 3x^2-4y=0. You get:

Factor:

Solve for each factor.

x - 2 = 0  so x = 2

3 x + 2 = 0 so x = - 2 / 3

Do the same technique for the next one.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.