Question

determine the best method to solve each system of equation.then solve the system.
1.x+2y=3; x+y=1
2.m+6n=-8; m=2n+8
3.a-b=6; a=2b+7
4.4x+y=15; -x-3x=-12
5.3c-d=14; c-d=2
6.x+2y=-9; y=4x

Answer 1

easy method is to substitute the value of one variable of one equation in the other equation,

Answer 2

suppose for 1
x=3-2y
substitute x=3-2y in the second equation x+y=1

Answer 3

which gives (3-2y) + y = 1
\[\rightarrow\]

3 - y = 1
y = 2
now from my previous comment x = 3 - 2y = 3 - 2(2) = -1

Answer 4

thanks