Question

How to solve this equation?

Answer 1

It says use the substitution method, so you would take the bottom equation, and since it says that x is equal to that, you would use that equation in place of the x in the top equation. so it would be 9y = 3(3y+3) - 9. You then distribute the 3 into the 3y +3, which gets you 9y = 9y + 9 - 9, which is also 9y=9y. Subtract 9y to get 0 = 0, which just means that there are infinite solutions to this equation. Whenever you get 0 = 0, all that means is that there are infinite solutions to this particular set of equations. Hope this helped!

Answer 2

Answer:

y=y

x=3y+3

Step-by-step explanation:

$\left \{ {{9y=3x-9} \atop {x=3y+3}} \right.$

$9y=3x-9$

Plug the second equation $x=3y+3$ into the above equation as x

$9y=3(3y+3)-9$

Open up the brackets

$9y=3(3y+3)-9\\9y=9y+9-9\\9y=9y\\y=y$

This system of equations has infinitely many solutions.

When graphed, the two lines will overlap each other.

Therefore, y=y and x=3y+3.

I hope this helps!