Question

Given the system of linear equations.

-x + y = 5, 4x + y = 10
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Answer 1

x = 1 and y = 6

Explanation:

`\left\{\begin{array}{ccc}-x+y=5\\4x+y=10&\text{change the signs}\end{array}\right\\\underline{+\left\{\begin{array}{ccc}-x+y=5\\-4x-y=-10\end{array}\right}\qquad\text{add both sides of the equations}\\.\qquad-5x=-5\qquad\text{divide both sides by (-5)}\\.\qquad x=1\\\\\text{put the value of x to the first equation}\\-1+y=5\qquad\text{add 1 to both sides}\\y=6`