Question

$x + y = 6 and x - y = 18 what is y$

Answer 1

x + y = 6 -------(1)

x - y = 18 -------(2)

On adding equation 1 and 2, we get

2x = 24

=> x = 12

Now,

On Substituting the value of x in equation 1, we get

12 + y = 6

=> y = 6 - 12

=> y = - 6

Answer 2

$x + y = 6 \\ \\ x - y = 18$
elimination method

X,X, get cancelled

2y=(-12)

y=-12/2

y=-6

substitute y value in X+y=6

X+(-6)=6

x-6=6

X=6+6

X=12

let's verify

12+(-6)

12-6=6

➡12-(-6)

12+6=18

so

X=12 and y=(-6)

hope it helps u