Question

Solve using substitution
3x - 9y = 3
6x - 3y = -24

Solve using elimination
y - 1/2x = 6
2x + 6y = 19

Answer 1

divide first equation by 3
x - 3 y = 1
so
x = (3y+1)
substitute that for x in the second equation after dividing the second equation by 3
2 (3y+1) - y = -8
6 y + 2 - y = -8
5 y = -10
y = -2
then x -3(-2) = 1
x + 6 = 1
x = -5

Answer 2

y - 1/2x = 6
is
-x + 2 y = 12
2x + 6y = 19
multiply first eqn by 2 again
-2x + 4 y = 24
+2x + 6 y = 19
============== add
0 + 10 y = 43
y = 4.3
4.3 -.5 x = 6
.5 x = -1.7
x = - 3.4