1. 若单项式$-x^{2}y^{a + 3}与单项式2x^{b - 1}y能合并为x^{2}y$,则$a + b$的值为( )
A.$0$
B.$1$
C.$-1$
D.$-2$
A.$0$
B.$1$
C.$-1$
D.$-2$
答案:
B
2. 下列结论正确的是( )
①$\frac{1}{4}(x^{2} + y)$是一个二次多项式;②多项式$\frac{1}{3}(xy - x^{2} - y^{2})的系数是\frac{1}{3}$;③多项式是整式;④多项式$x^{2} + xy - 7的次数是4$;⑤$\frac{1}{2x} + x - y$是多项式.
A.①②③④
B.①③
C.②③⑤
D.①④⑤
①$\frac{1}{4}(x^{2} + y)$是一个二次多项式;②多项式$\frac{1}{3}(xy - x^{2} - y^{2})的系数是\frac{1}{3}$;③多项式是整式;④多项式$x^{2} + xy - 7的次数是4$;⑤$\frac{1}{2x} + x - y$是多项式.
A.①②③④
B.①③
C.②③⑤
D.①④⑤
答案:
B
3. 给出下列式子:$\frac{xy}{4}$,$3a$,$\pi$,$\frac{x - y}{4}$,$1$,$3a^{2} + 1$,$1 + y$,其中单项式的个数是( )
A.$1$
B.$2$
C.$3$
D.$4$
A.$1$
B.$2$
C.$3$
D.$4$
答案:
D
4. 多项式$x^{2} - kxy + 5xy - 1中不含xy$的项,则$k$的值为( )
A.$3$
B.$4$
C.$5$
D.$6$
A.$3$
B.$4$
C.$5$
D.$6$
答案:
C
5. 下列各式中,与$-3a^{3}b^{2}$是同类项的是( )
A.$3a^{3}b$
B.$b^{2}a^{3}$
C.$b^{2}a^{2}$
D.$-3ab$
A.$3a^{3}b$
B.$b^{2}a^{3}$
C.$b^{2}a^{2}$
D.$-3ab$
答案:
B
6. 下列计算中,正确的是( )
A.$6a + 4b = 10ab$
B.$7x^{2}y - 3x^{2}y = 4x^{4}y^{2}$
C.$7a^{2}b - 7ba^{2} = 0$
D.$8x^{2} + 8x^{2} = 16x^{4}$
A.$6a + 4b = 10ab$
B.$7x^{2}y - 3x^{2}y = 4x^{4}y^{2}$
C.$7a^{2}b - 7ba^{2} = 0$
D.$8x^{2} + 8x^{2} = 16x^{4}$
答案:
C
7. 下列去括号正确的是( )
A.$x^{2} - (x - 3y) = x^{2} - x - 3y$
B.$x^{2} - 3(y^{2} - 2xy) = x^{2} - 3y^{2} + 2xy$
C.$m^{2} - 4(m - 1) = m^{2} - 4m + 4$
D.$a^{2} - 2(a - 3) = a^{2} + 2a - 6$
A.$x^{2} - (x - 3y) = x^{2} - x - 3y$
B.$x^{2} - 3(y^{2} - 2xy) = x^{2} - 3y^{2} + 2xy$
C.$m^{2} - 4(m - 1) = m^{2} - 4m + 4$
D.$a^{2} - 2(a - 3) = a^{2} + 2a - 6$
答案:
C
8. 已知$M = 2a + b$,$N = 4a - 3b$,则$2M - N$的结果为( )
A.$-2b$
B.$-b$
C.$4b$
D.$5b$
A.$-2b$
B.$-b$
C.$4b$
D.$5b$
答案:
D
9. 如图,这是2025年12月的日历,用随意圈出五个数,所圈的五个数的和一定( )


A.能被$2$整除
B.能被$3$整除
C.能被$4$整除
D.能被$5$整除
|日|一|二|三|四|五|六|
| | $1$ | $2$ | $3$ | $4$ | $5$ | $6$ |
| $7$ | $8$ | $9$ | $10$ | $11$ | $12$ | $13$ |
| $14$ | $15$ | $16$ | $17$ | $18$ | $19$ | $20$ |
| $21$ | $22$ | $23$ | $24$ | $25$ | $26$ | $27$ |
| $28$ | $29$ | $30$ | $31$ | | | |
A.能被$2$整除
B.能被$3$整除
C.能被$4$整除
D.能被$5$整除
|日|一|二|三|四|五|六|
| | $1$ | $2$ | $3$ | $4$ | $5$ | $6$ |
| $7$ | $8$ | $9$ | $10$ | $11$ | $12$ | $13$ |
| $14$ | $15$ | $16$ | $17$ | $18$ | $19$ | $20$ |
| $21$ | $22$ | $23$ | $24$ | $25$ | $26$ | $27$ |
| $28$ | $29$ | $30$ | $31$ | | | |
答案:
D
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