150k views
3 votes
Solve the following system of equations by linear combination: 3x+2y=7 y=x-4

1 Answer

0 votes

\left \{ {{3x+2y=7} \atop {y=x-4}} \right.

Express
y from first equation:

2y=7-3x

y=(7-3x)/(2)

Then, replace
y in second equation with found value and solve it:

(7-3x)/(2)=x-4

7-3x=2x-8

5x=15

x=15/5=3

Now, replace
x in first equation with found value and solve it too:

3*3+2y=7

9+2y=7

2y=-2

y=-2/2=-1

So the result is:
x=3 and
y=-1

User Kevin Maxwell
by
8.5k points

No related questions found