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The expansion of the number system of the third volume of mathematics and Science in the third year of the people's Education Press When Z is what number, Z & sup2; + 3Z + 2 is a real number? Please give the standard process,
Let z = a + bi, where a and B are real numbers
Take Z into the formula Z & sup2; + 3Z + 2 and dissolve it
a^2+(2ab+3b)i+3a-b^2
If the above formula is real, then (2Ab + 3b) I = 0
If the above formula is zero, then
2ab+3b=0
There is
a= -3/2
B is any real number
Step by step, it's still standard. If the answer is satisfied, please use it
Why plural? Under what circumstances?
The question you mentioned is quite common in English. Now the explanation is as follows:
Mathematical is an adjective, mathematical
Mathematics is a noun form, mathematics
There are many ways to use the plural form of an adjective as a singular noun in English
Good adjective, OK
Goods n
Electronic adjective, electronic,
Electronics noun, electronic products
－－－－－－－－－－－－－－－
The whole meaning of that question is
This meeting needs the participation of math teachers in the city
There should be a lot of math teachers in the city,
I hope I can forgive you for your mistakes
Why do animals use plural here?
The tiger had become a kind of rare animals.
Is it wrong?
I'm sorry, had was wrongly typed just now. It should be has. I know the tiger refers to a class. Since the singular has is used in the front, why not use animal in the back?
I can't write down the comments
I think so, too! The tiger has become a kind of rare animal
I think the singular should be used after a kind of
Now I don't have a grammar book on hand, so I can't look it up
A kind of animals
No matter what kind it means, it doesn't matter what
The problem here is not universal designation, but collocation
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