《2025年暑假Happy假日七年级理科五四制》

18. 已知方程组$\begin{cases}3x + y = -1,\\2x - 3y = -8.\end{cases}$
(1)$x$分别取$-3,-1,0,2$,填写下面的表格:
| $3x + y = -1$的解 | | | | |
| --- | --- | --- | --- | --- |
| $x$ | $-3$ | $-1$ | $0$ | $2$ |
| $y$ | 8 | 2 | -1 | -7 |
| $2x - 3y = -8$的解 | | | | |
| $x$ | $-3$ | $-1$ | $0$ | $2$ |
| $y$ | $\frac{2}{3}$ | 2 | $\frac{8}{3}$ | 4 |
(2)根据(1)中数据写出方程组的解.$\begin{cases}x=-1\\y = 2\end{cases}$

答案：
(1)
| $3x + y = -1$的解 | | | | |
| --- | --- | --- | --- | --- |
| $x$ | $-3$ | $-1$ | $0$ | $2$ |
| $y$ | $8$ | $2$ | $-1$ | $-7$ |
| $2x - 3y = -8$的解 | | | | |
| $x$ | $-3$ | $-1$ | $0$ | $2$ |
| $y$ | $\frac{2}{3}$ | $2$ | $\frac{8}{3}$ | $4$ |
(2)$\begin{cases}x=-1\\y = 2\end{cases}$

19. 甲、乙两人共同解方程组$\begin{cases}ax + 5y = 15,\\4x - by = -2,\end{cases}$由于甲看错了方程组中的$a$,得到方程组的解为$\begin{cases}x = -3,\\y = -1,\end{cases}$乙看错了方程组中的$b$,得到方程组的解为$\begin{cases}x = 5,\\y = 4,\end{cases}$试计算$a^{2021} + (-\frac{1}{10}b)^{2022}$的值.0

答案： $0$