Question

Solve these simultaneous equations by eliminating:
1) 7x - y = 9
2x + 3y = 19
2) x - 3y = 0
3x + y = 30
3) 7x - y = 19
2x + 3y = 12

Answer 1

I'll do one; you try the others, using the same method.
7x - y = 9
2x + 3y = 19
to eliminate y, multiply the 1st by 3 to get
21x - 3y = 27
2x + 3y = 19
Now if you add the equations, the y terms are eliminated, giving
23x = 46
x = 2
so, y = 5

The others work the same way.

Answer 2

Solve the following pair of linear equation by the elimination method and the substitution method 2 X + 3 y is equal to 0 and X + y is equal to 1