i'd be really grateful if someone could complete this simultaneous equation with working out explaining each stage of the process. thanks.

y = 2x + 3

x2 + y2 = 2

Printable View

- Jul 3rd 2010, 06:58 AMtylerdurdensimultaneous equation help
i'd be really grateful if someone could complete this simultaneous equation with working out explaining each stage of the process. thanks.

y = 2x + 3

x2 + y2 = 2 - Jul 3rd 2010, 07:04 AMProve It
I assume that the two equations are:

and .

Substituting into equation 2 gives

.

Now expand, collect like terms, and solve. - Jul 3rd 2010, 07:08 AMeumyang
- Jul 3rd 2010, 07:20 AMtylerdurden
cheers guys. appreciate the help.

the only bit i'm not too sure on is how to get from

x2 + (2x+3)2 = 2 to

x2 + 4x2 + 12x = 9 =2

would really appreciate if you could explain what i have to do.

thanks. - Jul 3rd 2010, 07:35 AMProve It
Remember that .

Expand it out. - Jul 3rd 2010, 07:57 AMtylerdurden
4x2 + 6x + 6x + 9

thanks for the help! - Jul 3rd 2010, 08:55 AMtylerdurden
not quite sure how you get from

(x+1) (5x +7) = 0

to

x= -1 y = 7/5

and why

thanks - Jul 3rd 2010, 07:04 PMProve It
When you have two numbers being multiplied together to give , that means at least one of them has to be .

So if then or .