How do you solve $2 x - y = 3$ $2x - y = 3$ and $3 x - y = 4$ $3x - y = 4$ using substitution?

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Answer 1 · 2016-05-01T20:29:17

An alternative method of solving them.
$x = 1 and y = - 1$ $x = 1 and y = -1$

Both of these equations contain the single variable $y$ $y$ .
Transpose them to make $y$ $y$ the subject.

$y = 3 x - 4$ $y = 3x - 4$ ....... and ....... $y = 2 x - 3$ $y = 2x - 3$

Now, because $y = y$ $y = y$ , it follows that

................. $3 x - 4 = 2 x - 3$ $3x - 4 = 2x - 3$ (giving an equation with one variable)

Solving it gives: $x = 1$ $x = 1$

There are now two ways to calculate the value of $y$ $y$

$y = 3 (1) - 4$ $y = 3(1) -4$ = -1 and $y = 2 (1) - 3$ $y = 2(1) - 3$ = -1

How do you solve 2x - y = 32x−y=32x - y = 3 and 3x - y = 43x−y=43x - y = 4 using substitution?