System of Equations

y=x-5
3x+y=7

Solve?


Sagot :

Y=x-5
-y=3x-7
Add them together
0=4x-12
12=4x
X=3
Y=-2
[tex]\sf{y=x-5}[/tex]
[tex]\sf{3x+y=7}[/tex]

Lets solve this by substitution.

Lets plug in y=x-5 into 3x+y=7

So:

[tex]\sf{y=x-5}[/tex]
[tex]\sf{3x+y=7}[/tex]

Plugging it in:

[tex]\sf{3x+(x-5)=7}[/tex]

Solve for x by simplifying that:

[tex]\sf{3x+x-5=7}[/tex]

[tex]\sf{4x-5=7}[/tex]

Add 5 on both sides

[tex]\sf{4x=12}[/tex]

Divide by 4 on both sides

[tex]\sf{x=3}[/tex]

Now simply plug x=3 back into any equation and solve for y

So:
[tex]\sf{y=x-5}[/tex]

[tex]\sf{y=3-5}[/tex]

Simplify that:

[tex]\sf{y=-2}[/tex]

So we are left with our final answer which is
[tex]\boxed{\bf{(3,-2)}}[/tex]