用消元法解线性方程组<img src="https://huaweicloudobs.ahjxjy.cn/2C3186F0F953E430948505F83A598894.png" title="1.png" alt="1.png"/><img src="https://huaweicloudobs.ahjxjy.cn/7431B7E8919E06BBA67328C631475CE4.png" title="x1.png" alt="x1.png"/>[填空],<img src="https://huaweicloudobs.ahjxjy.cn/9EC7EF50C7C734EA70834C00143C7E66.png" title="x2.png" alt="x2.png"/>[填空],<img src="https://huaweicloudobs.ahjxjy.cn/8FEE7AAB6ED3CB1B2BAC443126B1F165.png" title="x3.png" alt="x3.png"/>[填空],<img src="https://huaweicloudobs.ahjxjy.cn/DEC571DD29E87285D6AD9D2D3CCFACD5.png" title="x4.png" alt="x4.png"/>[填空].