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1. 甲、乙两数的和是30，若甲数为x，甲数的3倍与乙数的$\frac{2}{3}$的和用代数式表示是（
A.$3(30-x)+\frac{2}{3}x$
B.$3x+\frac{2}{3}×30$
C.$3x+\frac{2}{3}(30-x)$
D.$3(30-x)+\frac{2}{3}$
C
）A.$3(30-x)+\frac{2}{3}x$
B.$3x+\frac{2}{3}×30$
C.$3x+\frac{2}{3}(30-x)$
D.$3(30-x)+\frac{2}{3}$
答案
1.C
2. 某农场2024年的粮食产量为$a$，以后每年比上年增长$p\%$，那么2026年该农场的粮食产量是（
A.$a(1+p)^2$
B.$a(1+p\%)^2$
C.$a+a(p\%)^2$
D.$a+ap^2$
B
）A.$a(1+p)^2$
B.$a(1+p\%)^2$
C.$a+a(p\%)^2$
D.$a+ap^2$
答案
2.B
3. 下列各式计算正确的是 （
A.$a^2 - 2(a - b + c) = a^2 - 2a + b + c$
B.$(a + b) - (b - c) = a + 2b - c$
C.$(a + c) - 2(b + d) = a - 2b + c - 2d$
D.$[a - (b - c)][a + (b + c)] = (a - b + c)(a + b - c)$
C
）A.$a^2 - 2(a - b + c) = a^2 - 2a + b + c$
B.$(a + b) - (b - c) = a + 2b - c$
C.$(a + c) - 2(b + d) = a - 2b + c - 2d$
D.$[a - (b - c)][a + (b + c)] = (a - b + c)(a + b - c)$
答案
3.C
