Respuesta :

heyhi1347

example:

y=3x+5

y=9

substitute 9 in for y because they are both equal to y

(y)

9=3x+5

-5. -5

4=3x

4/3=x

put the 4/3 (which is x) in the first equation.

(x)

y=3(4/3)+5

y=4+5

y=9