2x + y = 5
-x + 3y = 4
求下列线性系统的解.
通过替代或消除方法可以找到这个线性方程系统的解.使用替代方法,我们可以用一个方程来解决一个未知数,然后将这个值替换到第二个方程中,以解决剩余的未知数.我们将使用这个未知数的计算值来使用这两个方程中的任何一个来解决另一个变量.让我们使用替代来解决这个系统:从第一方程中,我们可以用 x 计算 y: 2x + y = 5 y = 5 - 2x.现在我们可以用 y 的这个表达式替换到第二个方程中: -x + 3y = 4 -x + 3(5 - 2x) 4 - 15 + 6x = 4 -7x = 11 x = 11/7 x.现在我们可以用 x 替换这个值,我们可以使用第二方程的第一个方程.所以,我们将使用 y = 2x (2x + 5x = 13x = 5x = 5x = 5x = 5x = 5x = 5x = y = 22x = y = 7x = 5x = 5x = 5x = 5x = 5x = 5x = 5x = y = 13x = 7x = 7x = 7x = y = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x = 7x)