Question

If 6x-3y=30 and 4x=2-y then find x+y

Answer 1

x =( 30 - 3y)/6
y = 2 - 4x

x + y = (30-3y)/6 + (2-4x)

Answer 2

x=(30-3(2-4x))/6
x=(30-6+12x)/6
x=(24+12x)/6
x=4+2x
-x=4
so x=-4
and y=2-4x
so y=2-4*(-4)
y=2+16
y=18

Answer 3

x+y= -4+18
x+y=14

Answer 4

\[\{6 x-3 y=30,4 x=2-y\}\]The solutions to the above equations is:
x=2 and y=-6
x+y=-4
- - - - - - - - - - - -
4 x = 2 - y
y = 2 - 4x
6 x - 3 y = 30
6x - 3(2 - 4x) = 30
6x - 6 + 12x = 30
18x = 36
x = 2
y = 2 - 4x
y = 2 - 4*2
y = -6