simultaneous

[Guest]

1.Solve the simultaneous equations graphically on graph paper and then check your answer by non-graphical method
27V1 = 71I1 + 15I2
18V2 = 48I2 + 15I1
i dont understand this its like it has 3 or 4 unknowns i only know how to do 2 any help would be great

[Guest]

I think, since the question specifically refers to "simultaneous equations", $l1$ and $l2$ are to be considered the "unknowns" while $V1$ and $V2$ are to be considered "parameters". That is, "solve for $l1$ and $l2$ in terms of $V1$ and $V2$.

To do it on graph paper, the best I can think of is to take $V1$ and $V2$ equal to 1.

[Guest]

Have you got the answer to this? I also think that 'I1 and I2 need to be solved taking V1 and V2 as constant.

[Guest]

The given equations are
71I1 + 15I2= 27V1 and
48I2 + 15I1= 18V2

For the first equation, when l2= 0, l1= 27V1/71 and when l1= 0, l2= 27V1/15.
On an l1, l2 graph, mark (27V1/71, 0) and (0, 27V1/15). The graph is the straight line through those two points.

For the second equation, when l2= 0, l1= 18V2/15= 6V2/5 and when l1= 0, l2= 18V2/48= 3V2/8.
On an l1, l2 graph, mark (6V2/5, 0) and (0, 3V2/8). The graph is the straight line through those two points.