Solve the equation AX = B (where a and B are known numbers) There is no mistake in this question

Solve the equation AX = B (where a and B are known numbers) There is no mistake in this question

The first case: when a is 0, the equation has no solution
The second case: when a is not zero, the solution of the equation is x = B / A

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It is known that x is the smallest positive integer, y and Z are rational numbers, and the square of | 2 + y | + (3x + 2Z) = 0. Find the quadratic of formula - x + the quadratic of Y + 4xy + Z

x=1
|2+y|≥0
（3x+2z）^2≥0
|2+y|+（3x+2z）^2=0
∴|2+y|=0
（3x+2z）^2=0
∴y=-2
z=-3/2
The original formula = - (x) ^ 2 + y ^ 2 + (4xy + Z) / 4 = 5 / 8

In 2009, our province has promoted financial subsidies for 8.5 million energy-saving lamps. It is estimated that our province can save about 230 million yuan of electricity and reduce about 435000 tons of carbon dioxide in a year. Please estimate how many billion yuan of electricity can be saved and how many million tons of carbon dioxide can be reduced in a year? (the result is accurate to 0.1)

About 2.3/8.5 million × 5000 ≈ 1.35 billion yuan can be saved in one year;
About carbon dioxide emission reduction: 435 / 8.5 million × 5000 ≈ 2.559 million tons