Respuesta :
The first equation is 3 - x = 4 while the second equation is 12 = 9 - 3x.
By careful observation, we can see that both sides of the first equation has been multiplied by a constant factor 3 to form the second equation. Because this is an eqaution and both sides of the equation has been multiplied by thesame factor, the solution of the equation will remain the same because a balance is maintained.
Remember that to maintain a balance to an equation, whatever is done to one side of the equation must be done to the other side of the equation.
Thus,
3 + x = 4
After multiplying through by 3, we have
3( 3 + x ) = 3(4)
9 + 3x = 12
Since 3 is multiplying both sides of the equation, The solution to the equations remain equal
