Question

solve the following set of simultaneous equation x + y =24 ; 2 x -y =-6​

Answer 1

add both equation

$(x +y) + (2x - y) = 24 - 6 \\ x + y + 2x - y = 18 \\ 3x = 18 \\ x = 18 \div 3 \\ x = 6$

Answer 2

Answer:

x-y = 6 and x+y = 24

If we add the both equations we get

x+y + x-y = 2x =(6+24) = 30

2x = 30

x = 15

y = (24-15) = 9