Question

请帮忙解一个方程组,急用I1+I2+I3=05I1-10I3=15 求I1、 I2 、 I3的值,-10I2+10I3=

Answer 1

I1+I2+I3=0 (1)

5I1-10I3=15 (2)

-10I2+10I3=-65 (3)

(1)×10+(2)

15l1+10l2=15

3l1+2l2=3 (4)

(2)+(3)

5l1-10l2=-50

l1-2l2=-10 (5)

(4)+(5)

4l1=-7

l1=-7/4

l2=(3-3l1)/2=33/8

l3=-l1-l2=-19/8