I1 + I2 + I3 = 0, 20i1 + 6i3 = 140, 5i2 + 5i3 = 90, how to find the specific steps of the equation

I1 + I2 + I3 = 0, 20i1 + 6i3 = 140, 5i2 + 5i3 = 90, how to find the specific steps of the equation

5(I1+I2+I3)=0
5I2+5I3=90
5I1=-90
I1=-18
20I1+6I3=140
6I3=140+360
I3=250/3
I2=90/5-I3=-196/3

Let me solve the linear simultaneous equation I1 + I2 = I3, I1 + I3 = 180, I2 + I3 = 80,
I1 = 12, I2 = - 4, I3 = 8, w I calculated a lesson It's not right. Is it wrong in the book?

I3=86.6666667
I2=-6.6666667
I1=93.3333333
There must be something wrong in the book. Just put it into the formula and check it

I1+I2=I3 5I1+10I3=15 10I2+10I3=65

Substituting I3 = I1 + I2 into the following two formulas, 3i1 + 2I2 = 3 and 2i1 + 4i2 = 13 are obtained respectively
Multiply both sides of 3i1 + 2I2 = 3 by 26i1 + 4i2 = 6 minus 2i1 + 4i2 = 13 to calculate I1 = - 7 / 4, I2 = 33 / 8, I3 = 19 / 8

The distance between two places is 490 km. A and B start from two places and run in opposite directions. If they start at the same time, they will turn to the corner in 7 hours. If a drives for 7 hours, B starts,
Results two hours after B set out, the two cars met,

Two car speed x, y
7(x+y)=490
7x+2(x+y)=490
The results are as follows
x=50
y=20
A speed of 50 km / h, B speed of 20 km / h

In 2 + (4-3) + (6-5) + (8-7) + +What does 2 + 1 * [(2002-4) / 2 + 1] in (2000-1999) + (2002-2001) mean

It can be seen from the formula that 4-3,6-5,8-7 (2002-2001) this sequence, the first term, is 4,6,8 In 2002, the latter is 3, 5, 7 In 2001, they are all arithmetic sequences with 2 as tolerance, and 4-3, 6-5, 8-7 The results of (2002-2001) are all 1, so only 4, 6, 8 2002 or 3,5,7 2001, any

Which idiom can be used to describe the square of 1000 = 100 times 100 times 100

Do everything possible

The fruit shop brought 200 kg of apples, 25 kg less pears than apples, 50 kg more bananas than pears. How many kg bananas did the fruit shop bring?

225 kg

3A + 2B = 10, 2b + 2B = 8. Then a + B = (), A-B = ()

A+B=4 A-B=0

Z = I / 2-3i, what are the real and imaginary numbers

z=i/2-3i
=i(2+3i)/(2-3i)(2+3i)
=(-3+2i)/13
therefore
The real part is - 3 / 13
The imaginary part is 2 / 13

The fruit shop brought in a batch of fruits, including 20% less pears than apples, 20% less bananas than apples, and thousands of grams of bananas
600 kg

I don't think so. This kind of question should be an integer answer. The original question should be that the fruit store shipped a batch of 600 kg fruits, of which the pear is 20% less than the apple, and the banana is 20% more than the apple. How many kilogram bananas are there? This is the integer answer
Let the underlying apple be x, then there is the following relationship,
X+（1-20%）X+(1+20%)X=600
So we have 200 apples, 160 pears and 240 bananas