maths
posted by jenn on .
use the substitution method to solve the linear system.
1. 3x=9
x+2y=9
3x/3 = 9/3
x = 3
x(3)+2y = 9
3+2y = 9
2y = 12
y = 6
is (3,6) correct?
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also, can you please tell me how to solve these?
use the linear combinations to solve the linear system:
2.x+y=3
x+2y=6
3. x+y=7
y=2x+8
thanks

Yes, on (3.6)
2)
x+y=3
x+2y=6
subtract the second equation from the first:
x+y=3
(x+2y=6)
or the result is y=3
y=3
then go back and solve for x.