1. ## Simultaneous Equation help.

Hi guys, hoping this is the right forum.

I've got a Maths assignment I'm working on and I've completed the whole paper save one question. I'm really not sure how to go about doing this - here's the question:

5 = 0.4i1 + 1.8(i1-i2)
12 = 2.4i2 - 1.4(i1-i2)

Hope that's readable. I've tried substituting, but that (i1-i2) really throws me off. Anybody able to help?

2. Originally Posted by sebhaque
Hi guys, hoping this is the right forum.

I've got a Maths assignment I'm working on and I've completed the whole paper save one question. I'm really not sure how to go about doing this - here's the question:

5 = 0.4i1 + 1.8(i1-i2)
12 = 2.4i2 - 1.4(i1-i2)

Hope that's readable. I've tried substituting, but that (i1-i2) really throws me off. Anybody able to help?

$
0.4i_1 + 1.8(i_1 - i_2) = 0.4i_1 + 1.8i_1 - 1.8i_2 = 2.2i_1 - 1.8i_2 = 5$

$
2.4i_2 - 1.4(i_1 - i_2) = 2.4i_2 - 1.4i_1+1.4i_2 = 3.8i_2 - 1.4i_1= 12
$

$2.2i_1 - 1.8i_2 = 5$ (1)

$3.8i_2 - 1.4i_1= 12$ (2)

Solve in the standard way

3. Oh dear, I must have done far too much Maths today to have missed that!

Thanks very much for the quick response.