Science

Math

Humanities

... and beyond

Socratic Meta
Featured Answers

Topics

How do you solve the system of equations: x+y=3, 2x-y= -3?

1 Answer

Aug 6, 2015

Add the equations together to get an expression in terms o) $x$ $x$ , solve for $x$ $x$ , substitute the solution value back into one of the equations to solve for $y$ $y$
$XXXX$ $color(white)("XXXX")$ $(x, y) = (0, 3)$ $(x,y) = (0,3)$

Explanation:

[1] $XXXX$ $color(white)("XXXX")$ $x + y = 3$ $x+y=3$
[2] $XXXX$ $color(white)("XXXX")$ $2 x - y = - 3$ $2x-y = -3$

Adding [1] and [2]
[3] $XXXX$ $color(white)("XXXX")$ $3 x = 0$ $3x = 0$
Solve for $x$ $x$
[4] $XXXX$ $color(white)("XXXX")$ $x = 0$ $x=0$

Substitute $0$ $0$ for $x$ $x$ in [1] $[5]$ $[5]$ color(white)("XXXX")0 + y = 3#
Solve for $y$ $y$
[6] $XXXX$ $color(white)("XXXX")$ $y = 3$ $y = 3$

Related questions

See all questions in Linear Systems with Multiplication

Impact of this question

4550 views around the world

You can reuse this answer
Creative Commons License