Answer :

Answer:

3

Step-by-step explanation:

We are trying to solve the system using elimination (add).

To do this, we are being asked to change the first equation.

The answers 4 and -4 would not work because we are trying to eliminate the x value, and not the y value.

If we multiplied the top equation by -3, the top equation would be -9x+9y=-27

Let's test it out

  -9x+9y=-27

+ -9x+12y=-30

-18x+21y=-57

The answer -3 would not work, because as shown above, it does not eliminate anything.

If we multiplied the top equation by 3, the top equation would be 9x-9y=27.

Let's test it out

   9x-9y=27

+ -9x+12y=-30

          3y=-3

If we multiply 3 to the top equation, we can eliminate the x value. The answer is 3.

Answer: 3

Step-by-step explanation:

When eliminating x with addition, we would add the equations together. This means that the coefficients must add to 0.

If we multiply the top equation by 3, the equation becomes [tex]9x - 9y = 27[/tex]. When we add the equations, x would cancel because [tex]9x + (-9x) = 0[/tex].

This leaves [tex]3y = -3[/tex], which means [tex]y = -1[/tex]. When we plug [tex]y = -1[/tex] into either equation, we get [tex]x = 2[/tex]. This means the solution of the system is (2, -1).

However, for your purposes, the answer to click is 3.

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