Question

Find the x and y values: x-2y=3, x-y=-7

Answer 1

Have you considered subtracting the second equation from the first?

Answer 2

How would I do that?

Answer 3

\(\large\tt \begin{align} \color{black}{x-2y=3---A\\
x-y=-7----B
}\end{align}\)
multiply \(\Large B\) by \(\large -1\)
\(\large\tt \begin{align} \color{black}{ -(x-y)=-(-7)----B\\
-x+y=7--C}\end{align}\)
now add\(\large A\) and \(\large C\)
\(\large\tt \begin{align} \color{black}{x-2y=3---A\\
-x+y=7--C\\
(x-2y)+(-x+y)=(3)+(7)\\
x-2y-x+y=3+7\\
-y=10\\
\huge y=-10}\end{align}\)
now substitute value of \(\large y=-10\) in \(\Large C \) or \(\large B\)
and get the value of \(\large x\)

Answer 4

You should be up on subtraction. Just combine the like terms.

Answer 5

10-7=3

Answer 6

x-x = 0
-2y + y = -y
3 + 7 = 10

So, -y = 10 and y = -10

Substitute this value into either original equation and find x.