Question

Solve the following system of equations by using the substitution method.
x = y + 3
2x + y = 9

(4, 1)

(5, 2)

(3, -2)

Inconsistent

Answer 1

x = y + 3
2x + y = 9

Solution..
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Substitute for x=y+3 in the second equation...

2x+y = 9

2(y+3)+y=9

2y+6+y=9
3y+6=9
3y=9-6
3y=3
y=3/3
y=1....

Substitute for y=1 in the first equation...

x=y+3

x = 1+3
x=4..

Am sure the answer is quite evident now...